Illumination apparatus and illumination system

ABSTRACT

An illumination apparatus includes: a case having an opening portion; a light source disposed in the case and including a plurality of light-emitting elements; a light diffuser which is disposed in the opening portion, and diffuses and transmits light emitted from the plurality of light-emitting elements; and a controller that controls light emission from the light source. The controller: controls light emission from the plurality of light-emitting elements to project an image on the light diffuser, the image changing with time; and when changing the light emission from the plurality of light-emitting elements changing the image, controls the light emission from the light source to keep a change in at least one of (i) a light amount, (ii) a color temperature, and (iii) a spectral distribution of light emitted from the illumination apparatus within a predetermined range.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of Japanese PatentApplication Number 2017-059791 filed on Mar. 24, 2017, Japanese PatentApplication Number 2017-061973 filed on Mar. 27, 2017, Japanese PatentApplication Number 2017-061985 filed on Mar. 27, 2017, Japanese PatentApplication Number 2017-064017 filed on Mar. 28, 2017, Japanese PatentApplication Number 2017-065504 filed on Mar. 29, 2017, and JapanesePatent Application Number 2017-065697 filed on Mar. 29, 2017, the entirecontents of which are hereby incorporated by reference.

BACKGROUND 1. Technical Field

The present disclosure relates to an illumination apparatus and anillumination system that provide a user with a realistic feeling oflooking at the sky through a window from indoors.

2. Description of the Related Art

Conventionally, an illumination apparatus is disclosed which includes alight source that emits light and a light guide plate having a flat exitsurface through which the light from the light source exits (seeJapanese Unexamined Patent Application Publication No. 2016-12540(Patent Literature (PTL) 1), for example). This illumination apparatushas minute projections and recesses in the exit surface of the lightguide plate. Even when the light is yellowish, the projections andrecesses cause the light to scatter and complement blue light, so thatthe exiting light achieves color uniformity.

SUMMARY

With such an illumination apparatus, the exiting light achieves coloruniformity by light scattering. However, when, for example, an imagethat changes with time like the sky is projected on the illuminationapparatus, a person near the illumination apparatus may feel strangedepending on the projection condition.

The present disclosure has an object to provide an illuminationapparatus and related technologies capable of reducing a feeling ofstrangeness generated when projecting a changing image.

In order to achieve the above object, an illumination apparatusaccording to an aspect of the present disclosure includes: a case havingan opening portion; a light source disposed in the case, the lightsource including a plurality of light-emitting elements; a lightdiffuser which is disposed in the opening portion, and diffuses andtransmits light emitted from the plurality of light-emitting elements;and a controller that controls light emission from the light source. Thecontroller: controls light emission from the plurality of light-emittingelements to project an image on the light diffuser, the image changingwith time; and when changing the light emission from the plurality oflight-emitting elements changing the image, controls the light emissionfrom the light source to keep a change in at least one of (i) a lightamount, (ii) a color temperature, and (iii) a spectral distribution oflight emitted from the illumination apparatus within a predeterminedrange.

An illumination system according to an aspect of the present disclosureincludes: the illumination apparatus described above; light-emittingequipment including a light-emitting source different from the pluralityof light-emitting elements of the illumination apparatus; and anillumination controller that controls light emission from theillumination apparatus and light emission from the light-emittingequipment. The illumination controller: controls the light emission fromthe plurality of light-emitting elements to project an image on thelight diffuser of the illumination apparatus, the image changing withtime; and when changing the light emission from the plurality oflight-emitting elements changing the image, controls the light emissionfrom the light-emitting equipment to keep a change in at least one of(i) a light amount, (ii) a color temperature, and (iii) a spectraldistribution of light emitted from the illumination system within apredetermined range.

According to an illumination apparatus according to an aspect of thepresent disclosure, it is possible to reduce a feeling of strangenessgenerated when a changing image is projected. Moreover, according to anillumination system according to an aspect of the present disclosure, itis possible to reduce a feeling of strangeness generated when a changingimage is projected.

BRIEF DESCRIPTION OF DRAWINGS

The figures depict one or more implementations in accordance with thepresent teaching, by way of examples only, not by way of limitations. Inthe figures, like reference numerals refer to the same or similarelements.

FIG. 1 is a diagram illustrating a schematic configuration of anillumination system according to Embodiment 1;

FIG. 2 is a perspective view illustrating a first luminaire according toEmbodiment 1;

FIG. 3 is an exploded perspective view illustrating parts of the firstluminaire according to Embodiment 1;

FIG. 4 is a perspective view illustrating a schematic configuration of asecond luminaire according to Embodiment 1;

FIG. 5 is a fragmentary sectional view schematically illustrating aninternal structure of the second luminaire according to Embodiment 1;

FIG. 6 is a ceiling plan illustrating a positional relationship among alight diffuser, a lens, and a projection area according to Embodiment 1in a horizontal direction;

FIG. 7 is a diagram illustrating a schematic configuration of anillumination system according to Variation 1;

FIG. 8 is a diagram illustrating a schematic configuration of anillumination system according to Variation 2;

FIG. 9 is a diagram illustrating a schematic configuration of anillumination system according to Variation 3;

FIG. 10 is a diagram illustrating a schematic configuration of anillumination system according to Variation 4;

FIG. 11 is a diagram illustrating a schematic configuration of anillumination system according to Embodiment 2;

FIG. 12 is a perspective view illustrating a first luminaire accordingto Embodiment 2;

FIG. 13 is an exploded perspective view illustrating parts of the firstluminaire according to Embodiment 2;

FIG. 14 is a block diagram illustrating a control configuration of theillumination system according to Embodiment 2;

FIG. 15 is a schematic diagram illustrating a display screen when anapplication for setting environment reproduction condition is executedby a smartphone that is an exemplary mobile terminal according toEmbodiment 2;

FIG. 16 is a schematic diagram illustrating a display screen when aspecified area or a specified date and time is inputted on a smartphonethat is an exemplary mobile terminal according to Embodiment 2;

FIG. 17 is a flow chart illustrating a sequence of steps of anillumination control method according to Embodiment 2;

FIG. 18 is a schematic diagram illustrating an example when anenvironment in a space according to Variation 5 is caused to change overtime;

FIG. 19 is a schematic diagram illustrating an example when anenvironment in a space according to Variation 5 is caused to change overtime;

FIG. 20 is a perspective view illustrating an exterior appearance of anillumination apparatus according to Embodiment 3;

FIG. 21 illustrates the illumination apparatus according to Embodiment 3installed in a ceiling;

FIG. 22 is an exploded perspective view of a portion of the illuminationapparatus according to Embodiment 3;

FIG. 23 is a block diagram illustrating a control configuration of theillumination apparatus according to Embodiment 3;

FIG. 24 is a flow chart for displaying an image on the illuminationapparatus according to Embodiment 3;

FIG. 25 illustrates the amount of light of images projected on theillumination apparatus according to Embodiment 3;

FIG. 26 illustrates the color temperature of images projected on theillumination apparatus according to Embodiment 3;

FIG. 27 illustrates another example of images projected on theillumination apparatus according to Embodiment 3;

FIG. 28 is a perspective view illustrating an illumination apparatusaccording to Variation 6 installed in a ceiling;

FIG. 29 is a block diagram illustrating a control configuration of theillumination apparatus according to Variation 6;

FIG. 30 is a flow chart for displaying an image on the illuminationapparatus according to Variation 6;

FIG. 31 illustrates the spectral distribution of images projected on theillumination apparatus according to Variation 6;

FIG. 32 is a perspective view illustrating an illumination systemaccording to Variation 7;

FIG. 33 is a block diagram illustrating a control configuration of theillumination system according to Variation 7;

FIG. 34 illustrates images projected on an illumination apparatusaccording to another variation;

FIG. 35 is a perspective view illustrating an exterior appearance of anillumination apparatus according to Embodiment 4;

FIG. 36 illustrates the illumination apparatus according to Embodiment 4installed in a ceiling;

FIG. 37 is an exploded perspective view of portions of the illuminationapparatus according to Embodiment 4;

FIG. 38 is a cross sectional view of the illumination apparatusillustrated in FIG. 36, taken along line XXXVIII-XXXVIII;

FIG. 39 is a block diagram illustrating a control configuration of theillumination apparatus according to Embodiment 4;

FIG. 40 illustrates an example of a light emission state of theillumination apparatus according to Embodiment 4;

FIG. 41 illustrates Example 1 of the light emission state of theillumination apparatus according to Embodiment 4;

FIG. 42 illustrates Example 2 of the light emission state of theillumination apparatus according to Embodiment 4;

FIG. 43 illustrates Example 3 of the light emission state of theillumination apparatus according to Embodiment 4;

FIG. 44 is a cross sectional view of an illumination system according toVariation 8;

FIG. 45 is a block diagram illustrating a control configuration of theillumination system according to Variation 8;

FIG. 46 is a cross sectional view illustrating examples of a lightemission component of an illumination apparatus according to othervariations according to Embodiment 4;

FIG. 47 is a cross sectional view of an illumination apparatus accordingto another variation according to Embodiment 4;

FIG. 48 is a block diagram illustrating a control configuration of theillumination apparatus according to another variation according toEmbodiment 4;

FIG. 49 is a cross sectional view of an illumination apparatus accordingto another variation according to Embodiment 4;

FIG. 50 is a perspective view of external appearance of an illuminationapparatus according to Embodiment 5;

FIG. 51 is a perspective view of external appearance of the illuminationapparatus according to Embodiment 5 from which a case is removed;

FIG. 52 is an exploded view of the illumination apparatus according toEmbodiment 5;

FIG. 53 is a diagram for illustrating a difference in how lightreflected by a light reflector according to Embodiment 5 looks,depending on the presence or absence of a diffusion treatment on thelight reflector;

FIG. 54 is a cross-sectional view of the illumination apparatusaccording to Embodiment 5, taken along line LIV-LIV in FIG. 51;

FIG. 55 is a conceptual diagram illustrating exemplary installation ofthe illumination apparatus according to Embodiment 5;

FIG. 56 is a perspective view of external appearance of an illuminationapparatus according to Embodiment 6;

FIG. 57 is a perspective view of external appearance of the illuminationapparatus according to Embodiment 6 from which a case is removed;

FIG. 58 is an exploded perspective view of the illumination apparatusaccording to Embodiment 6;

FIG. 59 is a cross-sectional view of the illumination apparatusaccording to Embodiment 6, taken along line LIX-LIX in FIG. 57;

FIG. 60 is a diagram for explaining reflection of light reflected by anupright portion and entering a light diffuser depending on the presenceor absence of an antireflection layer;

FIG. 61 is a conceptual diagram illustrating exemplary installation ofthe illumination apparatus according to Embodiment 6;

FIG. 62 is a cross-sectional view of an illumination apparatus accordingto Variation 9, taken along line LIX-LIX in FIG. 57;

FIG. 63 is an enlarged cross-sectional view of the illuminationapparatus according to Variation 9, in a dashed region in FIG. 62; and

FIG. 64 is a fragmentary plan view of the illumination apparatusaccording to Variation 9, in a state in which a light diffuser isomitted from FIG. 57.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, Embodiments 1 to 6 of the present disclosure will bedescribed with reference to the drawings. A configuration for achievingthe above object will be described in Embodiment 3. Although each of theother embodiments has a unique object, it is possible to provide a moreeffective illumination apparatus and illumination system by combiningEmbodiment 3 and one or more of the other embodiments.

Moreover, the embodiments described below each represent a generic orspecific example. As such, the numerical values, shapes, materials,structural components, the arrangement and connection of the structuralcomponents, etc. shown in the following embodiments are mere examples,and are not intended to limit the scope of the present disclosure.Therefore, among the structural components in the following embodiments,structural components not recited in any one of the independent claimswhich indicate the broadest concepts of the present disclosure aredescribed as optional structural components.

Furthermore, the expression “substantially . . . ,” described here using“substantially rectangular” as an example, is intended to include notonly something that is exactly rectangular but also something that isacknowledged to be substantially rectangular. To put it differently,“substantially” used in the Specification means within manufacturingerrors and dimensional tolerances. In addition, the expression“approximately . . . ,” described here using “approximately aligned” asan example, is intended to include not only something that is completelyaligned but also something that is acknowledged to be approximatelyaligned. Stated differently, “approximately” used in the Specificationmeans within manufacturing errors and dimensional tolerances.

It should be noted that the figures are schematic diagrams and are notnecessarily precise illustrations. Furthermore, in the figures,substantially identical components are assigned the same referencesigns, and overlapping description may be omitted or simplified.

Furthermore, the drawings used for description in the followingembodiments may show coordinate axes. The negative side of the Z axisrepresents a floor side, and the positive side of the Z axis representsa ceiling side. Moreover, the X-axis direction and the Y-axis directionare orthogonal to each other on a plane perpendicular to the Z-axisdirection. The X-Y plane is a plane parallel to a light diffuser of anillumination apparatus. For example, in the following embodiments, “planview” means seeing from the Z-axis direction. In addition, for example,in the following embodiments, “section view” means seeing a crosssection of the illumination apparatus cut along a plane including asection line, from a perpendicular direction with respect to the crosssection. When, for example, the illumination apparatus is cut along aplane defined by the Y axis and the Z axis (an exemplary plane cut alonga section line), “section view” means seeing the section from the X-axisdirection.

Embodiment 1

Conventionally, illumination systems capable of reproducing illuminationby sunlight are known (e.g., see Japanese Unexamined Patent ApplicationPublication No. 2016-514340). The illumination system gives a user theimpression that light diffused by a light diffuser, which is part of theillumination system, looks like sunlight, by causing the user toperceive that an infinite space is present beyond the light diffuser.

The illumination system is, however, required to increase a distancebetween a light-emitting module and the light diffuser to allow the userto perceive a space beyond the light diffuser as the infinite space.Accordingly, the illumination system grows in size in a depth directionwith the increase in distance.

In view of this, Embodiment 1 has an object to provide an illuminationsystem and an illumination method that are capable of giving theimpression that emitted light looks like sunlight, without having toincrease a distance between a light-emitting module and a lightdiffuser.

[Illumination System]

The following describes illumination system A1 according to Embodiment 1of the present disclosure.

FIG. 1 is a diagram illustrating a schematic configuration ofillumination system A1 according to Embodiment 1. As illustrated in FIG.1, illumination system A1 includes: first luminaire A100 that is of aninternal lighting type; and second luminaire A200 that is of aprojection type, and these luminaries are disposed in, for example, samespace AH defined by a room in a building. Here, space AH is a spaceclosed to a certain degree, and is defined by, for example, a corridor,a staircase, a bathroom, a kitchen, a toilet, an entrance, and a hallother than a room. Illumination system A1 is suitable for being disposedin, for example, space AH having no windows because illumination systemA1 is capable of reproducing virtual sunlight. It should be noted thatluminaries (first luminaire A100 and second luminaire A200) can be alsoreferred to as illumination apparatuses.

Space AH is created by ceiling surface Ah1, floor surface Ah2, and wallsurfaces Ah3. In Embodiment 1, a case is described in which firstluminaire A100 and second luminaire A200 are disposed on ceiling surfaceAh1.

[First Luminaire]

Next, the following describes first luminaire A100. FIG. 2 is aperspective view illustrating first luminaire A100 according toEmbodiment 1. FIG. 3 is a perspective view illustrating parts of firstluminaire A100 according to Embodiment 1.

As illustrated in FIG. 2 and FIG. 3, first luminaire A100 includes caseA10, light-emitting module A20, light reflector A30, light diffuser A40,controller A50, and power source A60.

Case A10 is a box-like case body that houses light-emitting module A20,light reflector A30, light diffuser A40, controller A50, and powersource A60.

Case A10 includes housing portion A11 and frame portion A12.

Housing portion A11 is a housing body that houses light-emitting moduleA20, light reflector A30, light diffuser A40, controller A50, and powersource A60. It should be noted that house controller A50 and powersource A60 need not be housed in housing portion A11, and may bedisposed, for example, outside of case A10. Housing portion A11 has anopening in a bottom surface on a side facing floor surface Ah2, andhouses light diffuser A40 to cover the opening.

Frame portion A12 is a frame-like member having a substantiallyrectangular shape in a plan view, and is disposed in an edge portion ofthe bottom surface of housing portion A11. Light diffuser A40 is framedand held by frame portion A12. In consequence, light diffuser A40 isexposed from the opening of frame portion A12. Moreover, frame portionA12 is embedded in a ceiling so that surface A121 opposite to housingportion A11 in frame portion A12 is flush with ceiling surface Ah1. Forthis reason, light diffuser A40 is disposed farther back than surfaceA121 of frame portion A12.

Light-emitting module A20 is a light source for emitting firstillumination light having a color simulating a sky. As illustrated inFIG. 3, light-emitting module A20 is fixed to an end portion of lightreflector A30 opposite to light diffuser A40. Light-emitting module A20includes board A21 and first light sources A22 mounted on board A21.

Board A21 is a printed circuit board for mounting first light sourcesA22 and is formed in a substantially rectangular shape.

First light sources A22 are, for example, light-emitting elements suchas light-emitting diodes (LEDs). In Embodiment 1, first light sourcesA22 are RGB-type LEDs that emit red light, green light, and blue light.First light sources A22 are disposed on a surface of board A21 on a sidefacing floor surface Ah2. For example, first light sources are disposedin a matrix on the surface of board A21 on the side facing floor surfaceAh2. It should be noted that LEDs may be surface-mount device (SMD) LEDsor chip-on board (COB) LEDs.

In Embodiment 1, first light sources A22 are capable of emitting lighthaving various colors, by adjusting luminance of blue light, greenlight, and red light, because first light sources A22 are the RGB-typeLEDs.

Light reflector A30 is an optical member that is disposed to surroundfirst light sources A22 and has reflectivity for light emitted by firstlight sources A22. In other words, light reflector A30 reflects lightemitted by first light sources A22 and entering light reflector A30. InEmbodiment 1, light reflector A30 is a frame-like member surroundingfirst light sources A22, and reflects light with an inner surfacethereof.

Light reflector A30 is produced by, for example, performing a diffusiontreatment on a reflecting plate made of a metal material such asaluminum (Al) and having a mirror surface. Examples of the diffusiontreatment include a frosting treatment such as an anodizing treatment.It should be noted that the diffusion treatment may be performed atleast on the inner surface of light reflector A30.

Light diffuser A40 has translucency and diffusibility for light emittedfrom light-emitting module A20. Light diffuser A40 is produced by, forexample, diffusion processing on a resin material such as transparentacryl or polyethylene terephthalate (PET) or on a transparent plate madeof glass. Light diffuser A40 is a rectangular plate in a plan view.Light diffuser A40 is fixed to an end portion of light reflector A30opposite to light-emitting module A20. In other words, light diffuserA40 is opposite to light-emitting module A20 and is disposed to coverlight-emitting module A20. As a result, light emitted fromlight-emitting module A20 and light reflected by light reflector A30 arediffused and emitted outward by light diffuser A40. In this case, lightemitted by respective first light sources A22 of light-emitting moduleA20 is diffused by light diffuser A40, and becomes mixed togetherwithout causing granular appearance thereof. This allows light diffuserA40 to emit, for example, the first illumination light having the colorsimulating the sky such as a blue sky, a cloudy sky, and an evening skywithout causing a sense of discomfort. In other words, light diffuserA40 is a light emitter that emits the first illumination light havingthe color simulating the sky. Light diffuser A40, the light emitter,represents a color simulating a virtual sky over a whole area. Byobserving light diffuser A40 from there, a user receives an impressionas if the user were looking at a sky.

It should be noted that light emitted from respective first lightsources A22 of light-emitting module A20 is emitted from light diffuserA40 with going through no wavelength converter layer because there areno other components between light diffuser A40 and light-emitting moduleA20.

Controller A50 is a control device that controls operations oflight-emitting module A20 such as lighting up, turning off, dimming, andtoning (adjustment of a color of emitted light or a color temperature).For example, controller A50 obtains information about a display imagestored in a storage (not shown), and causes light-emitting module A20 toreproduce the display image according to the information. Specifically,when displaying a blue sky, controller A50 obtains information about theblue sky from the storage, and controls light-emitting module A20 basedon the information obtained. It should be noted that controller A50 andlight-emitting module A20 (first light sources A22) are electricallyconnected via a signal line.

In Embodiment 1, first light sources A22 are the RGB-type LEDs. For thisreason, controller A50 outputs a control signal to first light sourcesA22 via the signal line, the control signal including information aboutluminance of each of blue LEDs, green LEDs, and red LEDs. First lightsources A22 receiving the control signal emit blue light, green light,and red light based on the control signal.

Controller A50 is implemented by, for example, a microcomputer, aprocessor, or a dedicated circuit. In Embodiment 1, controller A50 isdisposed on a surface of light-emitting module A20 opposite to lightdiffuser A40.

Power source A60 is, for example, a power converter circuit thatconverts AC power supplied from a power system such as a commercialpower source, into DC power. Power source A60 includes a power circuitthat generates power for causing first light sources A22 oflight-emitting module A20 to emit light. For example, power source A60converts AC power supplied from a commercial power source into DC powerhaving a predetermined level, by rectifying, smoothing, stepping down,etc. the AC power, and supplies the DC power to light-emitting moduleA20. Power source A60 is electrically connected to the power system via,for example, a power line.

[Second Luminaire]

Next, the following describes second luminaire A200.

Second luminaire A200 is a luminaire that projects, on an object, secondillumination light having a color simulating sunlight. Specifically, asillustrated in FIG. 1, second luminaire A200 creates projection area AFby projecting second illumination light AL2 having a color simulatingsunlight on an object composed of floor surface Ah2 and wall surface Ah3among the surfaces defining space AH. When light diffuser A40 of firstluminaire A100 is assumed to be a window, projection area AF virtuallyrepresents a sunny place created on wall surface Ah3 by sunlight passingthrough the window. Second luminaire A200 further may be a kind ofspotlight. Second luminaire A200 may be a cutter spotlight which iscapable of changing a shape of light. Any kind of light which is capableof changing its lighting area or lighting color may be adapted to secondluminaire A200.

In other words, first luminaire A100 virtually reproduces a sky, andsecond luminaire A200 virtually reproduces a sunny place and sunlightentering from the sky virtually reproduced by first luminaire A100.

The following describes second luminaire A200 in detail.

FIG. 4 is a perspective view illustrating a schematic configuration ofsecond luminaire A200 according to Embodiment 1. FIG. 5 is a fragmentarysectional view schematically illustrating an internal structure ofluminaire body A210 of second luminaire A200 according to Embodiment 1.

As illustrated in FIG. 4, second luminaire A200 is a spotlight andincludes: luminaire body A210 that is cylindrical; and pair of arms A220that holds luminaire body A210. As illustrated in FIG. 1, secondluminaire A200 is installed in the ceiling so that luminaire body A210is exposed from installation opening Ah4 provided in ceiling surfaceAh1.

As illustrated in FIG. 5, luminaire body A210 includes board A211,second light source A212, wavelength converter layer A213, lens A214,mask A215, and supporting member A216.

Board A211 is a board on which second light source A212 is mounted, andincludes a metal line for supplying power to second light source A212.

Second light source A212 is, for example, a light-emitting element suchas an LED. In Embodiment 1, second light source A212 is, for example, ablue LED that emits blue light. It should be noted that the blue LED maybe a surface-mount device (SMD) LED or a chip-on board (COB) LED. Inaddition, it is possible to use, as second light source A212, a laserdiode other than an LED.

Wavelength converter layer A213 is a sealing layer that seals secondlight source A212. Specifically, wavelength converter layer A213includes a translucent resin material containing, as a wavelengthconverter material, yellow phosphor particles. Although, for example, asilicon resin is used as the translucent resin material, an epoxy resinor a urea resin may be used. As the yellow phosphor particles, yttriumaluminum garnet (YAG)-based phosphor particles are used, for example.

With this configuration, the wavelength of a portion of the blue lightemitted by second light source A212 is converted by the yellow phosphorparticles contained in wavelength converter layer A213, which transformsthe portion into yellow light. Subsequently, the blue light not absorbedby the yellow phosphor particles and the yellow light resulting from thewavelength conversion by the yellow phosphor particles are diffused andmixed. As a result, light having a color (white color) simulatingsunlight is emitted from wavelength converter layer A213.

Lens A214 is a lens that controls distribution of light emitted fromwavelength converter layer A213. Specifically, lens A214 is, forexample, a biconvex lens and is disposed opposite to wavelengthconverter layer A213.

Mask A215 partially blocks light passing through lens A214 to providesecond illumination light AL2. Specifically, mask A215 is a plateincluding a translucent member, and has opening A215 a in the centerarea. Mask A215 is disposed opposite to lens A214, and a portion of lensA214 is exposed from opening A215 a. Light passing through opening A215a becomes second illumination light AL2 to create projection area AF. Inother words, the plan view shape of opening A215 a determines the shapeof projection area AF. Lens A214 the portion of which is exposed fromopening A215 a of mask A215 is a projector that projects, on an object,second illumination light AL2 having a color simulating sunlight.

Supporting member A216 is, for example, a metal case and includes boardA211, second light source A212, wavelength converter layer A213, lensA214, and mask A215. Supporting member A216 is a member that gives anexternal appearance to luminaire body A210, and is supported by pair ofarms A220 as illustrated in FIG. 4.

Pair of arms A220 is horizontally rotatable in installation opening Ah4(see arrow AY1 in FIG. 4). In addition, pair of arms A220 holdsluminaire body A210 vertically rotatably (see arrow AY2 in FIG. 4). Itis possible to adjust the orientation of luminaire body A210 bycombining horizontal rotation of pair of arms A220 and vertical rotationof luminaire body A210. Accordingly, it is also possible to adjust thelocation of projection area AF.

In Embodiment 1, it is assumed that the orientation of luminaire bodyA210 is manually adjusted. For this reason, when second luminaire A200is installed in installation opening Ah4, an installer adjusts theorientation of luminaire body A210 in advance so that projection area AFis created at a desired location. Here, the desired location is alocation in which a sunny place is estimated to appear when lightdiffuser A40 of first luminaire A100 is assumed to be a window andsunlight enters from the window.

It should be noted that providing a drive source for adjusting theorientation of second luminaire A200 to second luminaire A200 makes itpossible to automatically adjust the orientation of luminaire body A210.

As shown in FIG. 5, second luminaire A200 includes controller A250 andpower source A260.

Controller A250 is a control device that is electrically connected tosecond light source A212 and controls operations of second light sourceA212 such as lighting up and turning off. Controller A250 is implementedby, for example, a microcomputer, a processor, or a dedicated circuit.

Power source A260 is, for example, a power converter circuit thatconverts AC power supplied from a power system such as a commercialpower source, into DC power. Power source A260 includes a power circuitthat generates power for causing second light sources A212 to emitlight. For example, power source A260 converts AC power supplied from acommercial power source into DC power having a predetermined level, byrectifying, smoothing, stepping down, etc. the AC power, and suppliesthe DC power to second light source A212. Power source A260 iselectrically connected to the power system via, for example, a powerline.

[Conditions for Second Illumination Light]

In Embodiment 1, it is assumed that second illumination light hasluminance and a color temperature that are constant. Here, when thesecond illumination light satisfies conditions including a luminancecondition and a color temperature condition, the second illuminationlight makes it possible to give reality to sunlight imitated by thesecond illumination light, using compositive visual effects with firstillumination light emitted by first luminaire A100.

The luminance condition is defined as a condition in which arelationship between the real sky and sunlight is specified byluminance. Specifically, the luminance condition is defined as acondition in which, when the light emitter (light diffuser A40 of firstluminaire A100) and the projector (lens A214 of second luminaire A200)are observed from a place not illuminated by second illumination lightAL2, the light emitter is greater in luminance than the projector. Inother words, when the light emitter is observed from the place notilluminated by second illumination light AL2, the projector appearsdark. Stated differently, when a user observes the light emitter fromthe place not illuminated by second illumination light AL2, it ispossible to strongly impress a sky reproduced by the light emitter onthe user because the projector becomes less prominent from the place notilluminated by second illumination light AL2.

Moreover, the luminance condition may be defined as a condition inwhich, when the light emitter (light diffuser A40 of first luminaireA100) and the projector (lens A214 of second luminaire A200) areobserved from a place illuminated by second illumination light AL2, thelight emitter is less in luminance than the projector. In other words,when the light emitter is observed from the place illuminated by secondillumination light AL2, the projector appears brighter. Stateddifferently, it is possible to impress, on the user, a shine when thesun is seen from a window.

It should be noted that at least one of the above-described luminanceconditions may be satisfied. When the two luminance conditions aresatisfied, it is possible to produce a more effective dramatic impact.

The color temperature condition is defined as a condition in which arelationship between the real sky and a sunny place is specified by acolor temperature. Specifically, the color temperature condition isdefined as a condition in which second illumination light AL2 is lowerin color temperature than the first illumination light. For example, ina relationship between a real blue sky and a sunny place, the blue skyhas a color temperature of at least 10000 K and at most 15000 K, and thesunny place has a color temperature of at least 4000 K and at most 6500K. It should be noted that the blue sky may have a color temperature ofat least 10000 K and at most 12000 K. In addition, the sunny place mayhave a color temperature of at least 6000 K and at most 6500 K.

In a relationship between a real evening sky and a sunny place, theevening sky has a color temperature of at least 3000 K and at most 3500K, and the sunny place has a color temperature of at least 2000 K and atmost 2700 K. As above, regarding a relationship between a daytime skyand a sunny place, the sunny place is lower in color temperature thanthe sky in either of the cases. In other words, as described above,under the color temperature condition in which second illumination lightAL2 is lower in color temperature than the first illumination light, itis possible to surely reproduce a virtual sky and a sunny place usingthe first illumination light and second illumination light AL2.

[Positional Relationship Among Elements]

Next, the following describes a positional relationship among lightdiffuser A40 of first luminaire A100, lens A214 of second luminaireA200, and projection area AF.

As illustrated in FIG. 1, light diffuser A40 and lens A214 are higherthan projection area AF by being disposed on ceiling surface Ah1.Sunlight streams down from mostly above during daytime. In other words,when light diffuser A40 is higher than projection area AF, firstluminaire A100 and projection area AF make it possible to reproduce apositional relationship between the real sun and a sunny place.

Next, the following describes a positional relationship among lightdiffuser A40, lens A214, and projection area AF in a horizontaldirection. FIG. 6 is a ceiling plan illustrating a positionalrelationship among light diffuser A40, lens A214, and projection area AFaccording to Embodiment 1 in a horizontal direction. In other words,FIG. 6 illustrates the positional relationship among the elements whenlight diffuser A40 is seen in a plan view. It should be noted that FIG.6 illustrates projection area AF which is increased in thickness for thepurpose of convenience.

Second illumination light AL2 projected from lens A214 creates a shadowon projection area AF. Moreover, as mentioned above, projection area AFis created at the location in which the sunny place is estimated toappear when light diffuser A40 of first luminaire A100 is assumed to bethe window and the sunlight enters from the window. For this reason, itis desirable to give the impression that the shadow created onprojection area AF also looks like a shadow created by the sunlight.

As illustrated in FIG. 6, when reference plane AS100 that is a planeperpendicular to a plane when light diffuser A40 is seen in a plan viewand that includes normal line AN passing the center of projection areaAF is considered a boundary, a portion on the left of reference planeAS100 is referred to as first region AR1, and a portion on the right ofreference plane AS100 is referred to as second region AR2, lightdiffuser A40 and lens A214 are both in first region AR1. In other words,when light diffuser A40 is seen in a plan view, light diffuser A40 andlens A214 are both on the same side with reference plane AS100 as theboundary.

As just described, when light diffuser A40 and lens A214 are in firstregion AR1, sunlight AL10 entering from the window when light diffuserA40 is assumed to be the window and second illumination light AL2projected from center AS2 of lens A214 travel in almost the samedirection. In other words, the shadow created on projection area AF bysecond illumination light AL2 also extends in almost the same directionas a shadow created by sunlight AL10. Accordingly, it is possible togive the impression that the shadow created on projection area AF lookslike the shadow created by sunlight AL10.

As a comparative example, a case will be described in which lightdiffuser A40 is in first region AR1 and lens A214A is in second regionAR2. In this case, sunlight AL10 entering from a window when lightdiffuser A40 is assumed to be the window and second illumination lightAL3 projected from the center of lens A214A significantly differ intraveling direction. In other words, a shadow created on projection areaAF by second illumination light AL3 extends in a direction completelydifferent from a direction in which a shadow created by sunlight AL10extends, which gives the user a sense of discomfort.

For these reasons, in the case where light diffuser A40 and lens A214are on the same side with reference plane AS100 as a boundary when lightdiffuser A40 is seen in a plan view, it is possible to give theimpression that the shadow created on projection area AF looks like theshadow created by sunlight AL10. In particular, it is possible to createa more real shadow on projection area AF because closely arranging lightdiffuser A40 and lens A214 allows sunlight AL10 and second illuminationlight AL2 to be as parallel to each other as possible.

It should be noted that, in Embodiment 1, the case is described in whichentire light diffuser A40 and entire lens A214 are on the same side withreference plane AS100 as the boundary when light diffuser A40 is seen ina plan view. It is sufficient, however, that centers AS1 and AS2 oflight diffuser A40 and lens A214 are on the same side.

Moreover, in Embodiment 1, the case is described in which projectionarea AF is created on wall surface Ah3. Meanwhile, it is sufficient thata plane that is perpendicular to a plane when light diffuser A40 is seenin a plan view and has normal line AN passing the center of projectionarea AF1 created on floor surface Ah2 is used as reference plane AS100also for projection area AF1.

[Advantageous Effects Etc.]

As described above, according to Embodiment 1, illumination system A1includes: first luminaire A100 that is of an internal lighting type andincludes a light emitter (light diffuser A40) that emits firstillumination light having a color simulating a sky; and second luminaireA200 that is of a projection type and includes a projector (lens A214)that projects, on an object (floor surface Ah2), second illuminationlight AL2 having a color simulating sunlight. First luminaire A100 andsecond luminaire A200 are disposed in same space AH, and first luminaireA100 is disposed higher with respect to a floor than projection area AFcreated on the object by second illumination light AL2.

With this configuration, since second luminaire A200, which projectssecond illumination light AL2 simulating the sunlight, is includedseparately from first luminaire A100, which emits the first illuminationlight having the color simulating the sky, it is possible to give theimpression that the light (first illumination light and secondillumination light AL2) emitted by first luminaire A100 and secondluminaire A200 looks like the sunlight, using compositive visual effectsof the sky reproduced by first luminaire A100 and the sunlight(projection area AF) reproduced by second luminaire A200. In otherwords, it is possible to give the impression that the light (firstillumination light and second illumination light AL2) emitted by firstluminaire A100 and second luminaire A200, without having to increase adistance between light-emitting module A20 and light diffuser A40 infirst luminaire A100.

Moreover, second illumination light AL2 is lower in color temperaturethan the first illumination light.

With this configuration, it is possible to surely reproduce a virtualsky and sunlight using the first illumination light and secondillumination light AL2.

Moreover, when the light emitter and the projector are observed from aplace not illuminated by second illumination light AL2, the lightemitter is higher in luminance than the projector.

With this configuration, when a user observes the light emitter from theplace not illuminated by second illumination light AL2, it is possibleto strongly impress a sky reproduced by the light emitter on the userbecause the projector becomes less prominent from the place notilluminated by second illumination light AL2.

Moreover, when the light emitter and the projector are observed from aplace illuminated by second illumination light AL2, the light emitter islower in luminance than the projector. When the light emitter isobserved from the place illuminated by second illumination light AL2,the projector appears brighter. Stated differently, it is possible toimpress, on the user, a shine when the sun is seen from a window.

Moreover, when the light emitter is seen in a plan view, the lightemitter and the projector are on a same side with a reference plane as aboundary, the reference plane being perpendicular to a plane defined inthe plan view, and including a normal line passing the center of theprojection area.

With this configuration, in the case where light diffuser A40 and lensA214 are on the same side with reference plane AS100 as a boundary whenlight diffuser A40 is seen in a plan view, it is possible to give theimpression that a shadow created on projection area AF looks like ashadow created by sunlight.

Moreover, first luminaire A100 and second luminaire A200 are disposed ona same surface (ceiling surface Ah1) among surfaces defining same spaceAH.

With this configuration, it is possible to dispose first luminaire A100and second luminaire A200 closer to each other because first luminaireA100 and second luminaire A200 are on the same surface. Consequently, itis possible to allow sunlight AL10 and second illumination light AL2 tobe as parallel to each other as possible, and create a more real shadowon projection area AF, sunlight AL10 entering, when light diffuser A40of first luminaire A100 is assumed to be a window, from the window.

Moreover, first luminaire A100 includes an LED as first light sourceA22, and light emitted from first light source A22 is emitted from thelight emitter with going through no wavelength converter layer.Furthermore, second luminaire A200 includes one of an LED and a laserdiode as second light source A212, and light emitted from second lightsource A212 is emitted from the projector via wavelength converter layerA213.

With this configuration, illumination system A1 including firstluminaire A100 not having the wavelength converter layer and secondluminaire A200 having wavelength converter layer A213 makes it possibleto give the impression that the light (first illumination light andsecond illumination light AL2) emitted by first luminaire A100 andsecond luminaire A200 looks like sunlight.

Moreover, first luminaire A100 further includes frame portion A12 thatholds the light emitter, and the light emitter is disposed farther backthan a surface of frame portion A12 on a side facing same space AH.

For example, when light diffuser A40, the light emitter, is flush withceiling surface Ah1, it seems to the user that the ceiling looks like athin plate, which may make it difficult to reproduce a real sky.However, when the light emitter is disposed farther back than thesurface of frame portion A12 on the side facing same space AH, it ispossible to reproduce a more real sky.

[Variation 1]

In Embodiment 1, the case is described in which first luminaire A100 andsecond luminaire A200 are disposed on the same surface (ceiling surfaceAh1) among the surfaces defining space AH. In Variation 1, a case isdescribed in which first luminaire A100 and second luminaire A200 aredisposed on different surfaces among the surfaces defining space AH. Itshould be noted that hereinafter descriptions of elements that areidentical to those in Embodiment 1 may be omitted.

FIG. 7 is a diagram illustrating a schematic configuration ofillumination system A1A according to Variation 1 of Embodiment 1. Asillustrated in FIG. 7, although second luminaire A200 is disposed onceiling surface Ah1 as with Embodiment 1, first luminaire A100 isdisposed on wall surface Ah3. In this case, it is possible to give animpression of first luminaire A100 as a wall window. Second luminaireA200 creates projection area AF2 on wall surface Ah3 different from wallsurface Ah3 in which first luminaire A100 is disposed. Here, sunlight isalmost horizontal light at sunrise or sunset. In this case, when atleast a portion of projection area AF is lower than light diffuser A40of first luminaire A100, it is possible to reproduce a sunny place atsunrise or sunset in projection area AF2. In other words, a positionalrelationship between first luminaire A100 and projection area AF2 inthis case is that first luminaire A100 is higher than projection areaAF2.

As just described, it is possible to increase layout flexibility becausefirst luminaire A100 and second luminaire A200 are disposed on thedifferent surfaces (wall surface Ah3 and ceiling surface Ah1) among thesurfaces defining space AH.

[Variation 2]

Moreover, in Embodiment 1, the case is described in which projectionarea AF is created on only one surface (wall surface Ah3) among thesurfaces defining space AH. A projection area, however, may becontinuously created on surfaces.

FIG. 8 is a diagram illustrating a schematic configuration ofillumination system A1B according to Variation 2 of Embodiment 1. Asillustrated in FIG. 8, projection area AF3 created by second luminaireA200 of illumination system A1B is continuously on wall surface Ah3 andfloor surface Ah2. In order to create such projection area AF3, it issufficient to adjust the orientation of luminaire body A210 of secondluminaire A200, adjust the shape or size of opening A215 a of mask A215,or the like.

As just described, projection area AF continuously created on theadjacent surfaces among the surfaces defining space AH makes it possibleto produce more various dramatic impacts.

[Variation 3]

Although, in Embodiment 1, the case is described in which firstluminaire A100 includes case A10, a first luminaire need not include acase. In this case, structural components (a light-emitting module, alight reflector, a light diffuser, a controller, a power source, etc.)of the first luminaire are directly installed in a ceiling.

FIG. 9 is a diagram illustrating a schematic configuration ofillumination system A1C according to Variation 3 of Embodiment 1. Asillustrated in FIG. 9, light diffuser A40 is disposed in opening Ah11 inceiling surface Ah1 and farther back than ceiling surface Ah1 becausefirst luminaire A100 c of illumination system A1C does not include acase. In other words, a light emitter may be disposed in opening Ah11 inone surface (ceiling surface Ah1) among the surfaces defining space AHand farther back than the one surface.

With this configuration, even when the case is absent, it is possible toreproduce a more real sky because the light emitter is disposed notflush with ceiling surface Ah1 but farther back than ceiling surfaceAh1.

[Variation 4]

Although, in Embodiment 1, the case is described in which firstluminaire A100 and second luminaire A200 are disposed at the differentlocations, a first luminaire and a second luminaire may be disposed atlocations in which the first luminaire and the second luminaire overlapwith each other. In other words, a projector of the second luminaire maybe inside a light emitter of the first luminaire.

FIG. 10 is a diagram illustrating a schematic configuration ofillumination system A1D according to Variation 4 of Embodiment 1. Asillustrated in FIG. 10, in Variation 4, entire luminaire body A210 ofsecond luminaire A200 d is disposed more inwardly than light diffuserA40 d (a light emitter) of first luminaire A100 d. Light-emitting moduleA20 d has through hole A29 through which second illumination light AL2of second luminaire A200 d passes. It should be noted that, when secondluminaire A200 d is outside of a case of first luminaire A100 d, athrough hole through which second illumination light AL2 passes may beprovided to the case.

As just described above, disposing the projector of second luminaireA200 inside light diffuser A40 d of first luminaire A100 d causes lightdiffuser A40 d to have luminance lower than luminance of the projector.

Other Variations of Embodiment 1

Although illumination system A1 according to Embodiment 1 has beendescribed above, the present disclosure is not limited to Embodiment 1.

For example, although, in Embodiment 1, the case is described in whichthe luminance and the color temperature of second illumination light AL2are held constant, it is possible that like first luminaire A100, secondluminaire A200 controls dimming and toning of second illumination lightAL2. In this case, second luminaire A200 may control the dimming andtoning of second illumination light AL2 in conjunction with dimming andtoning by first luminaire A100. When second luminaire A200 controls thedimming and toning of second illumination light AL2, as long as secondillumination light AL2 satisfies the above-described conditions (theluminance condition and the color temperature condition), it is possibleto reproduce a virtual sky and sunlight without causing a sense ofdiscomfort. Moreover, first luminaire A100 may control dimming andtoning of the first illumination light so that the first illuminationlight satisfies the conditions.

The second luminaire may be a luminaire other than a spotlight as longas the luminaire is of a projection type. Examples of the luminaireother than the spotlight include a projector device and a short-focusprojector device. It should be noted that examples of the projectordevice include an image projector device and an illumination projectordevice.

Furthermore, the light diffuser may be disposed in a recess formed inone of surfaces defining the same place.

Moreover, the illumination system includes: the first luminaire that isof an internal lighting type and includes the light diffuser that emitsfirst illumination light having a color simulating a sky; and the secondluminaire that is of a projection type and includes the lens thatprojects, on an object, the second illumination light having a colorsimulating sunlight. The first luminaire and second luminaire emit thefirst illumination light and the second illumination light,respectively, into a same space in which the object is disposed. Thefirst luminaire is disposed, in the space, at a location higher than theprojection area on the object created by the second illumination light.

Embodiment 2

Conventionally, illumination systems capable of reproducing illuminationby sunlight are known (e.g., see Japanese Unexamined Patent ApplicationPublication (Translation of PCT Application) No. 2016-514340). Theillumination system gives a user an impression that light diffused by adiffusing panel, which is part of the illumination system, looks likesunlight, by causing the user to perceive that infinite space is presentbeyond the diffusing panel.

In recent years, however, it is desired to reproduce variousenvironments with illumination light.

In view of this, Embodiment 2 has an object to provide an illuminationsystem and an illumination control method that are capable ofreproducing various environments with illumination light.

[Illumination System]

The following describes illumination system B1 according to Embodiment 2of the present disclosure.

FIG. 11 is a diagram illustrating a schematic configuration ofillumination system B1 according to Embodiment 2. As illustrated in FIG.11, illumination system B1 includes: first luminaire B100 that is of aninternal lighting type; and second luminaire B200 that is of aprojection type, and these luminaries are disposed in, for example, samespace BH defined by a room in a building. Here, space BH is a spaceclosed to a certain degree, and is defined by, for example, a corridor,a staircase, a bathroom, a kitchen, a toilet, an entrance, and a hallother than a room. Illumination system B1 is suitable for being disposedin, for example, space BH having no windows because illumination systemB1 is capable of reproducing virtual sunlight. It should be noted thatluminaries (first luminaire A100 and second luminaire A200) can be alsoreferred to as illumination apparatuses.

Space BH is created by ceiling surface Bh1, floor surface Bh2, and wallsurfaces Bh3. In Embodiment 2, a case is described in which firstluminaire B100 and second luminaire B200 are disposed on ceiling surfaceBh1.

[First Luminaire]

Next, the following describes first luminaire B100. FIG. 12 is aperspective view illustrating first luminaire B100 according toEmbodiment 2. FIG. 13 is a perspective view illustrating parts of firstluminaire B100 according to Embodiment 2.

It should be noted that except for a difference between controller A50and controller B50, first luminaire B100 can be configured in the samemanner as first luminaire A100 described in Embodiment 1.

As illustrated in FIG. 12 and FIG. 13, first luminaire B100 includescase B10, light-emitting module B20, light reflector B30, light diffuserB40, controller B50, and power source B60.

Case B10 is a box-like case body that houses light-emitting module B20,light reflector B30, light diffuser B40, controller B50, and powersource B60.

Case B10 includes housing portion B11 and frame portion B12.

Housing portion B11 is a housing body that houses light-emitting moduleB20, light reflector B30, light diffuser B40, controller B50, and powersource B60. It should be noted that house controller B50 and powersource B60 need not be housed in housing portion B11, and may bedisposed, for example, outside of case B10. Housing portion B11 has anopening in a bottom surface on a side facing floor surface Bh2, andhouses light diffuser B40 to cover the opening.

Frame portion B12 is a frame-like member having a substantiallyrectangular shape in a plan view, and is disposed in an edge portion ofthe bottom surface of housing portion B11. Light diffuser B40 is framedand held by frame portion B12. In consequence, light diffuser B40 isexposed from the opening of frame portion B12. Moreover, frame portionB12 is recessed in a ceiling so that surface B121 opposite to housingportion B11 in frame portion B12 is flush with ceiling surface Bh1. Forthis reason, light diffuser B40 is disposed farther back than surfaceB121 of frame portion B12.

Light-emitting module B20 is a light source for emitting firstillumination light having a color simulating a sky. As illustrated inFIG. 13, light-emitting module B20 is fixed to an end portion of lightreflector B30 opposite to light diffuser B40. Light-emitting module B20includes board B21 and first light sources B22 mounted on board B21.

Board B21 is a printed circuit board for mounting first light sourcesB22 and is formed in a substantially rectangular shape.

First light sources B22 are, for example, light-emitting elements suchas light-emitting diodes (LEDs). In Embodiment 2, first light sourcesB22 are RGB-type LEDs that emit blue light, green light, and red light.First light sources B22 are disposed on a surface of board B21 on a sidefacing floor surface Bh2. For example, first light sources are disposedin a matrix on the surface of board B21 on the side facing floor surfaceBh2. It should be noted that the LEDs may be surface-mount device (SMD)LEDs or chip-on-board (COB) LEDs.

In Embodiment 2, since first light sources B22 are the RGB-type LEDs,first light sources B22 are capable of emitting light having variouscolors, by adjusting luminance of blue light, green light, and redlight.

Light reflector B30 is an optical member that is disposed to surroundfirst light sources B22 and has reflectivity for light emitted by firstlight sources B22. In other words, light reflector B30 reflects lightemitted by first light sources B22 and entering light reflector B30. InEmbodiment 2, light reflector B30 is a frame-like member surroundingfirst light sources B22, and reflects light with an inner surfacethereof.

Light reflector B30 is produced by performing, for example, a diffusiontreatment on a reflecting plate made of a metal material such asaluminum (Al) and having a mirror surface. Examples of the diffusiontreatment include a frosting treatment such as an anodizing treatment.It should be noted that the diffusion treatment may be performed on atleast the inner surface of light reflector B30.

Light diffuser B40 has translucency and diffusibility for light emittedfrom light-emitting module B20. Light diffuser B40 is produced byperforming, for example, diffusion processing on a resin material suchas transparent acryl or polyethylene terephthalate (PET) or on atransparent plate made of glass. Light diffuser B40 is a rectangularplate in a plan view. Light diffuser B40 is fixed to an end portion oflight reflector B30 opposite to light-emitting module B20. In otherwords, light diffuser B40 is opposite to light-emitting module B20 andis disposed to cover light-emitting module B20. As a result, lightemitted from light-emitting module B20 and light reflected by lightreflector B30 are diffused and emitted outward by light diffuser B40. Inthis case, light emitted by respective first light sources B22 oflight-emitting module B20 is diffused by light diffuser B40, and becomesmixed together without causing granular appearance thereof. This allowslight diffuser B40 to emit, for example, the first illumination lighthaving the color simulating the sky such as a blue sky, a cloudy sky,and an evening sky without causing a sense of discomfort. In otherwords, light diffuser B40 is a light emitter that emits the firstillumination light having the color simulating the sky. Light diffuserB40, the light emitter, represents a color simulating a virtual sky overa whole area. By observing light diffuser B40, a user receives animpression as if the user were looking at a sky from there.

Controller B50 is a control circuit that controls operations oflight-emitting module B20 such as lighting up, turning off, dimming, andtoning (adjustment of a color of emitted light or a color temperature).For example, controller B50 obtains information about a display imagestored in a storage (not shown), and causes light-emitting module B20 toreproduce the display image according to the information. Specifically,when displaying a blue sky, controller B50 obtains information about theblue sky from the storage, and controls light-emitting module B20 basedon the information obtained.

Moreover, controller B50 can be configured to further have the followingfunction in addition to the function of controller A50. Controller B50is capable of reproducing cloud in the sky by controlling a distributionof a color and luminance expressed by light-emitting module B20. Itshould be noted that controller B50 and light-emitting module B20 (firstlight sources B22) are electrically connected via a signal line.

In Embodiment 2, first light sources B22 are the RGB-type LEDs. For thisreason, controller B50 outputs a control signal to first light sourcesB22 via the signal line, the control signal including information aboutluminance of each of blue LEDs, green LEDs, and red LEDs. First lightsources B22 receiving the control signal emit blue light, green light,and red light based on the control signal.

Controller B50 is implemented by, for example, a microcomputer, aprocessor, or a dedicated circuit.

In Embodiment 2, controller B50 is disposed on a surface oflight-emitting module B20 opposite to light diffuser B40.

Power source B60 is, for example, a power converter circuit thatconverts AC power supplied from a power system such as a commercialpower source, into DC power. Power source B60 includes a power circuitthat generates power for causing first light sources B22 oflight-emitting module B20 to emit light. For example, power source B60converts AC power supplied from a commercial power source into DC powerhaving a predetermined level, by rectifying, smoothing, stepping down,etc. the AC power, and supplies the DC power to light-emitting moduleB20. Power source B60 is electrically connected to the power system via,for example, a power line.

[Second Luminaire]

Next, the following describes second luminaire B200.

Second luminaire B200 is a luminaire that projects, on an object, secondillumination light having a color simulating sunlight to create a sunnyportion on the object. Specifically, as illustrated in FIG. 11, secondluminaire B200 creates sunny portion BF1 by projecting the secondillumination light having the color simulating the sunlight, on, as theobject, wall surface Bh3 among the surfaces defining space BH. Sunnyportion BF1 can be also referred to as a projection area. When lightdiffuser B40 of first luminaire B100 is assumed to be a window, sunnyportion BF1 virtually represents a sunny place created on wall surfaceBh3 by sunlight passing this window. It should be noted that in FIG. 11,a chain double-dashed line indicates the position of sun Bt1 creatingthe sunny place. Sunny portion BF1 is created on an extension of sun Bt1and the window.

Second luminaire B200 can be configured in the same manner as secondluminaire A200.

In other words, first luminaire B100 virtually reproduces a sky, andsecond luminaire B200 virtually reproduces a sunny place and sunlightentering from the sky virtually reproduced by first luminaire B100.

Examples of second luminaire B200 include a projector and a short-focusprojector. It should be noted that examples of the projector include animage projector and an illumination projector.

As illustrated in FIG. 11, second luminaire B200 includes projector lensB201 that emits projection light BL. Second luminaire B200 is installedin the ceiling so that projector lens B201 is exposed from installationopening Bh4 provided in ceiling surface Bh1. A projection range ofprojection light BL is set to overlap with entire one wall surface Bh3.Second luminaire B200 reproduces sunny portion BF1 by projecting animage on wall surface Bh3 using projection light BL. In other words, outof projection light BL, light reproducing sunny portion BF1 is thesecond illumination light having the color simulating the sunlight. Outof projection light BL, light other than the second illumination lightreproduces a background. The light reproducing the background is darkerthan at least the second illumination light. In addition, it isdesirable that the light reproducing the background be made bright tosuch a degree that the light does not cause discomfort to a color,pattern, etc. of wall surface Bh3.

Second luminaire B200 is capable of changing a position, shape, andcolor of sunny portion BF1 by controlling an image projected on wallsurface Bh3.

It should be noted that the projection range of projection light BL ofsecond luminaire B200 may cover the surfaces (ceiling surface Bh1, floorsurface Bh2, wall surfaces Bh3) defining space BH. In this case, it ispossible to create sunny portion BF1 covering the surfaces.

[Control Configuration]

Next, the following describes a control configuration of illuminationsystem B1. FIG. 14 is a block diagram illustrating a controlconfiguration of illumination system B1 according to Embodiment 2. Asillustrated in FIG. 14, illumination system B1 includes control deviceB300 that centrally controls first luminaire B100 and second luminaireB200. Control device B300 includes operation unit B310, communicationunit B320, and controller B330. Control device B300 is, for example, acontrol panel attached to wall surface Bh3 as illustrated in FIG. 11.

Operation unit B310 includes a touch panel, manual operation buttons,etc., and receives various instructions from a user. Examples of thevarious instructions include a power on/off instruction for firstluminaire B100 and second luminaire B200.

Communication unit B320 includes an antenna, a wireless module, etc.,and communicates with the Internet, an external device, etc.Specifically, communication unit B320 is, for example, an obtaining unitthat wirelessly communicates with mobile terminal B400 owned by the userand obtains an environment reproduction condition created by mobileterminal B400. The environment reproduction condition is a condition forreproducing a certain environment in space BH, and is used indetermining a color temperature, luminance, etc. of light (the firstillumination light and the second illumination light) emitted byluminaries B100 and B200.

Controller B330 includes a central processing unit (CPU), a memory,etc., and controls first luminaire B100 and second luminaire B200 basedon the various instructions received by operation unit B310 and theenvironment reproduction condition obtained by communication unit B320.Accordingly, the first illumination light emitted by first luminaireB100 and the second illumination light projected by second luminaireB200 are each caused to be light according to the environmentreproduction condition. This illumination control method will bedescribed later.

[Mobile Terminal]

Mobile terminal B400 may be a terminal that is carried and operable bythe user. Mobile terminal B400 may be, for example, a dedicated devicefor setting environment reproduction condition or an informationterminal such as a smartphone, a mobile phone, a tablet device, and alaptop computer. When mobile terminal B400 is an information terminal,mobile terminal B400 executes an application for setting environmentreproduction condition. When the user specifies a user's desiredenvironment according to this application, mobile terminal B400 createsan environment reproduction condition corresponding to the specifiedenvironment and outputs the environment reproduction condition tocommunication unit B320. Specifically, mobile terminal B400 allowsselection between a present position mode and a specification mode whenan environment reproduction condition is created.

FIG. 15 is a schematic diagram illustrating a display screen when anapplication for setting environment reproduction condition is executedby a smartphone that is an example of mobile terminal B400 according toEmbodiment 2. As illustrated in FIG. 15, display screen BG1 of mobileterminal B400 displays selection buttons Bb1 and Bb2, OK button Bb3, andcancel button Bb4. Out of selection buttons Bb1 and Bb2, selectionbutton Bb1 is for selecting the present position mode, and selectionbutton Bb2 is for selecting the specification mode. When the usertouches one of selection buttons Bb1 and Bb2 and subsequently touches OKbutton Bb3, mobile terminal B400 executes the mode corresponding to thetouched one of selection buttons Bb1 and Bb2. It should be noted thatwhen the user touches one of selection buttons Bb1 and Bb2 andsubsequently touches cancel button Bb4, mobile terminal B400 cancels theselection operation.

[Present Position Mode]

The present position mode is a mode in which a first environmentreproduction condition is created based on a present position ofillumination system B1. In the present position mode, mobile terminalB400 creates the first environment reproduction condition based onreference information and present position information about the presentposition of illumination system B1. The present position informationincludes the latitude and longitude of the present position ofillumination system B1, and a date and time and weather at the presentposition. Mobile terminal B400 may obtain the present positioninformation from the Internet or the present position informationinputted by the user.

Mobile terminal B400 calculates a position (an altitude and azimuth) ofsun Bt1 in the present position at the present time, based on thepresent position information. In addition, mobile terminal B400calculates a color and brightness of the sky and a color temperature andluminance of sunlight at the present time, based on the position of sunBt1 and the weather.

The reference information includes a size and position of wall surfaceBh3, the object, among the surfaces defining space BH in whichillumination system B1 is installed, and a size, shape, and position oflight diffuser B40, the light emitter of first luminaire B100. Thereference information is registered in mobile terminal B400 in advancebefore the illumination control method is executed.

Mobile terminal B400 calculates a shape and position of sunny portionBF1 projected on the object, based on the reference information and theposition of sun Bt1 at the present time. Specifically, mobile terminalB400 calculates a relative positional relationship between the objectand light diffuser B40 based on the size and position of wall surfaceBh3, the object, and the size, shape, and position of light diffuserB40. When the relative positional relationship and the position of sunBt1 at the present time are calculated, assuming that light diffuser B40is a window, it is possible to calculate a shape and position of anactual sunny place created on the object by the sunlight passing thewindow. Mobile terminal B400 calculates the shape and position of sunnyportion BF1 projected by second luminaire B200, based on the shape andposition of the actual sunny place.

The color and brightness of the sky at the present time, the colortemperature and luminance of the sunlight at the present time, and theshape and position of sunny portion BF1 thus calculated above constitutethe first environment reproduction condition. After creating the firstenvironment reproduction condition, mobile terminal B400 transmits thefirst environment reproduction condition to communication unit B320 ofillumination system B1.

[Specification Mode]

The specification mode is a mode in which a second environmentreproduction condition corresponding to an environment specified by theuser is created. Here, examples of the environment specified by the userinclude an area and a date and time. It should be noted thathereinafter, an area specified by the user is referred to as a“specified area,” and a date and time specified by the user is referredto as a “specified date and time.”

FIG. 16 is a schematic diagram illustrating a display screen when aspecified area or a specified date and time is inputted on a smartphonethat is an example of mobile terminal B400 according to Embodiment 2. Asillustrated in FIG. 16, display screen G2 of mobile terminal B400displays entry field Bi1, OK button Bb3, and return button Bb5. When theuser enters a specified area or a specified date and time in entry fieldBi1 and subsequently touches OK button Bb3, mobile terminal B400executes processing corresponding to the entry. It should be noted thatwhen the user touches return button Bb5, mobile terminal B400 goes backto previous display screen BG1.

First, the following describes processing when a specified area isentered in the specification mode. In this case, a specified date andtime is not entered.

Mobile terminal B400 creates the second environment reproductioncondition based on position information of the specified area andreference information. The position information of the specified areaincludes the latitude and longitude of a representative place in thespecified area, and a present date and time and weather at the place.Mobile terminal B400 obtains the position information of the specifiedarea from the Internet.

Mobile terminal B400 calculates a position (an altitude and azimuth) ofsun Bt1 in the specified area at the present time, based on the positioninformation of the specified area. Moreover, mobile terminal B400calculates a color and brightness of the sky and a color temperature andluminance of sunlight in the specified area at the present time, basedon the position of sun Bt1 and the weather. Furthermore, mobile terminalB400 calculates a shape and position of sunny portion BF1 projected onthe object, based on the reference information and the position of sunBt1 in the specified area at the present time.

The color and brightness of the sky in the specified area at the presenttime, the color temperature and luminance of the sunlight in thespecified area at the present time, and the shape and position of sunnyportion BF1 thus calculated above constitute the second environmentreproduction condition. After creating the second environmentreproduction condition, mobile terminal B400 transmits the secondenvironment reproduction condition to communication unit B320 ofillumination system B1.

Next, the following describes processing when a specified date and timeis further entered in the specification mode in addition to thespecified area.

The specified date and time may be precisely specified using a specificdate and time or may be specified on a daily basis, a monthly basis, ora seasonal basis. When a specified date and time is specified on a dailybasis, a specified date including a representative time (e.g., noon) ofthe day is the specified date and time. Moreover, when a specified dateand time is specified on a monthly basis or a seasonal basis, aspecified month or a representative date and time of a specified seasonis the specified date and time.

Mobile terminal B400 creates the second environment reproductioncondition based on date and time information of the specified date andtime, and the reference information. The date and time information ofthe specified date and time include the latitude and longitude of thepresent position of illumination system B1, the specified date and time,and weather on the specified date and time. Mobile terminal B400 obtainsthe date and time information of the specified date and time from theInternet.

Mobile terminal B400 calculates a position (an altitude and azimuth) ofsun Bt1 in the present position on the specified date and time, based onthe date and time information of the specified date and time. Inaddition, mobile terminal B400 calculates a color and brightness of thesky and a color temperature and luminance of sunlight in the presentposition on the specified date and time, based on the position of sunBt1 and the weather.

Furthermore, mobile terminal B400 calculates a shape and position ofsunny portion BF1 projected on the object, based on the referenceinformation and the position of sun Bt1 on the specified date and time.

The color and brightness of the sky on the specified date and time, thecolor temperature and luminance of the sunlight on the specified dataand time, and the shape and position of sunny portion BF1 thuscalculated above constitute the second environment reproductioncondition. After creating the second environment reproduction condition,mobile terminal B400 transmits the second environment reproductioncondition to communication unit B320 of illumination system B1.

It should be noted that the second environment reproduction conditionmay be created using both of the specified area and the specified dateand time.

[Illumination Control Method]

Next, the following describes the illumination control method executedby controller B330. FIG. 17 is a flow chart illustrating a sequence ofsteps of the illumination control method according to Embodiment 2.

First, in step BS1, controller B330 determines whether communicationunit B320 obtained an environment reproduction condition. Whendetermining that communication unit B320 did not obtain the environmentreproduction condition (NO in step BS1), controller B330 stands ready asbefore. When determining that communication unit B320 obtained theenvironment reproduction condition (YES in step BS1), controller B330proceeds to step BS2.

In step BS2, controller B330 determines whether the obtained environmentreproduction condition is a first environment reproduction condition.When determining that the obtained environment reproduction condition isthe first environment reproduction condition (YES in step BS2),controller B330 proceeds to step BS3. When determining that the obtainedenvironment reproduction condition is not the first environmentreproduction condition (NO in step B52), controller 300 determines thatthe obtained environment reproduction condition is a second environmentreproduction condition, and proceeds to step BS7.

In step BS3, controller B330 determines a color temperature andluminance of first illumination light to be emitted by first luminaireB100, based on the first environment reproduction condition.Specifically, controller B330 determines the color temperature andluminance of the first illumination light to be emitted by firstluminaire B100, based on a color and brightness of a sky at the presenttime included in the first environment reproduction condition.

In step BS4, controller B330 controls first luminaire B100 to cause thefirst illumination light to have the color temperature and luminancedetermined in step BS3. Accordingly, first luminaire B100 virtuallyreproduces the sky in the present position at the present time.

In step BS5, controller B330 determines a color temperature andluminance of second illumination light to be emitted by second luminaireB200 and a shape and position of sunny portion BF1 to be created by thesecond illumination light, based on the first environment reproductioncondition. Specifically, controller B330 determines the colortemperature and luminance of the second illumination light and the shapeand position of sunny portion BF1, based on a color temperature andluminance of sunlight and a shape and position of sunny portion BF1included in the first environment reproduction condition.

In step BS6, controller B330 controls second luminaire B200 to cause thesecond illumination light to have the color temperature and luminancedetermined in step BS5 and create sunny portion BF1 having the shape andposition determined in step BS5. In other words, when light diffuser B40of first luminaire B100 is assumed to be a window, second luminaire B200virtually reproduces, as sunny portion BF1, a sunny place created onwall surface Bh3 by sunlight at the present time passing the window.

In contrast, in step BS7, controller B330 determines a color temperatureand luminance of first illumination light to be emitted by firstluminaire B100, based on a second environment reproduction condition.Specifically, controller B330 determines the color temperature andluminance of the first illumination light to be emitted by firstluminaire B100, based on a color and brightness of a sky in a specifiedarea or on a specified data and time included in the second environmentreproduction condition.

In step BS8, controller B330 controls first luminaire B100 to cause thefirst illumination light to have the color temperature and luminancedetermined in step BS7. Accordingly, first luminaire B100 virtuallyreproduces the sky in the specified area or on the specified date andtime.

In step BS9, controller B330 determines a color temperature andluminance of second illumination light to be emitted by second luminaireB200 and a shape and position of sunny portion BF1 to be created by thesecond illumination light, based on the second environment reproductioncondition. Specifically, controller B330 determines the colortemperature and luminance of the second illumination light and the shapeand position of sunny portion BF1, based on a color temperature andluminance of sunlight and a shape and position of sunny portion BF1included in the second environment reproduction condition.

In step BS10, controller B330 controls second luminaire B200 to causethe second illumination light to have the color temperature andluminance determined in step BS9 and create sunny portion BF1 having theshape and position determined in step BS9. In other words, when lightdiffuser B40 of first luminaire B100 is assumed to be a window, secondluminaire B200 virtually reproduces, as sunny portion BF1, a sunny placecreated on wall surface Bh3 by sunlight in the specified area or on thespecified date and time passing the window.

[Advantageous Effects Etc.]

As described above, illumination system B1 according to Embodiment 2includes: first luminaire B100 that emits first illumination lighthaving a color simulating a sky; second luminaire B200 that is disposedin same space BH as first luminaire B100, second luminaire B200projecting, on an object (wall surface Bh3), second illumination lightsimulating sunlight to create sunny portion BF1 on the object; andcontroller B330 that causes first luminaire B100 to emit the firstillumination light according to an environment reproduction condition.

Moreover, an illumination control method according to Embodiment 2 is anillumination control method for controlling: first luminaire B100 thatemits first illumination light having a color simulating a sky; andsecond luminaire B200 that is disposed in same space BH as firstluminaire B100, second luminaire B200 projecting, on an object, secondillumination light simulating sunlight to create sunny portion BF1 onthe object. The illumination control method includes: obtaining anenvironment reproduction condition; and causing first luminaire B100 toemit the first illumination light according to the environmentreproduction condition.

The obtaining unit obtains environment reproduction conditionscorresponding to various environments. Since first luminaire B100 emitsthe first illumination light corresponding to the environmentreproduction conditions obtained by the obtaining unit, it is possibleto reproduce the various environments with the first illumination light.It is also possible to reproduce a real environment in same space BH asa result of a synergistic effect with sunny portion BF1 projected bysecond luminaire B200.

Moreover, controller B330 controls first luminaire B100 to cause atleast one of a color temperature and luminance of the first illuminationlight to correspond to the environment reproduction condition.

According to this configuration, at least one of the color temperatureand luminance of the first illumination light can be caused tocorrespond to the environment reproduction condition. With this, firstluminaire B100 is allowed to reproduce a virtual sky that is moresimilar to a desired environment.

Moreover, controller B330 causes second luminaire B200 to emit secondillumination light according to the environment reproduction conditionobtained by the obtaining unit.

In addition, in the illumination control method, second luminaire B200is caused to emit the second illumination light according to theenvironment reproduction condition.

According to this configuration, since second luminaire B200 emits thesecond illumination light corresponding to the environment reproductioncondition obtained by the obtaining unit, it is possible to reproducethe various environments with the first illumination light and thesecond illumination light.

Moreover, controller B330 controls second luminaire B200 to cause atleast one of a shape and a position of sunny portion BF1 created by thesecond illumination light and a color temperature and luminance of thesecond illumination light to correspond to the environment reproductioncondition.

According to this configuration, at least one of the shape and theposition of sunny portion BF1 created by the second illumination lightand the color temperature and the luminance of the second illuminationlight can be caused to correspond to the environment reproductioncondition. With this, second luminaire B200 is allowed to reproducesunny portion BF1 that is more similar to a desired environment.

Moreover, the obtaining unit obtains, as the environment reproductioncondition, an environment reproduction condition based on a presentposition of illumination system B1 (first environment reproductioncondition), which is created in a present position mode, and anenvironment reproduction condition specified by a user (secondenvironment reproduction condition), which is created in a specificationmode.

According to this configuration, since the obtaining unit obtains, asthe environment reproduction condition, the environment reproductioncondition based on the present position of illumination system B1 andthe environment reproduction condition specified by the user, it ispossible to selectively use any of the environment reproductionconditions. In particular, when the environment reproduction conditionbased on the present position of illumination system B1 is used, firstluminaire B100 and second luminaire B200 are capable of reproducing anenvironment in the present position at the present time. On the otherhand, when the environment reproduction condition specified by the useris used, first luminaire B100 and second luminaire B200 are capable ofreproducing an environment desired by the user.

Moreover, the obtaining unit obtains the environment reproductioncondition based on an area specified by the user in the specificationmode.

According to this configuration, since the obtaining unit obtains theenvironment reproduction condition based on the area specified by theuser in the specification mode, first luminaire B100 and secondluminaire B200 are capable of reproducing an environment of thespecified area desired by the user.

Moreover, the obtaining unit obtains the environment reproductioncondition based on a date and time specified by the user in thespecification mode.

According to this configuration, since the obtaining unit obtains theenvironment reproduction condition based on the date and time specifiedby the user in the specification mode, first luminaire B100 and secondluminaire B200 are capable of reproducing an environment on thespecified date and time desired by the user.

(Variation 5)

Embodiment 2 illustrates the case in which the environment reproduced byillumination system B1 is constant. Illumination system B1, however, isalso capable of causing a reproduced environment to change over time.Variation 5 of Embodiment 2 illustrates a case in which an environmentin space BH is caused to change over time by controlling first luminaireB100 and second luminaire B200 over time. It should be noted thathereinafter, descriptions of elements that are identical to those inEmbodiment 2 may be omitted.

Here, examples of a method for controlling first luminaire B100 andsecond luminaire B200 over time include a first method and a secondmethod. In the first method, mobile terminal B400 creates, for eachtiming of switching, an environment reproduction condition correspondingto the timing, and transmits the environment reproduction condition tocommunication unit B320 of control device B300. The timing of switchingis timing of switching manners of controlling first luminaire B100 andsecond luminaire B200. In other words, the timing of switching is timingwith which a reproduced environment is switched. In this case,controller B330 controls first luminaire B100 and second luminaire B200each time communication unit B320 obtains environment reproductioninformation. Accordingly, it is possible to cause an environment inspace BH to change over time.

Moreover, in the second method, mobile terminal B400 creates a timetable including temporal changes of an environment reproductioncondition, and transmits the time table to communication unit B320. Inthis case, controller B330 controls first luminaire B100 and secondluminaire B200 based on the time table obtained by communication unitB320. Accordingly, it is possible to cause an environment in space BH tochange over time.

FIG. 18 and FIG. 19 each are a schematic diagram illustrating an examplewhen an environment in space BH according to Variation 5 is caused tochange over time, and correspond to FIG. 11.

For example, it is assumed that sun Bt1 in FIG. 11, sun Bt2 in FIG. 18,and sun Bt3 in FIG. 19 are in the southeast, the south, and thesouthwest, respectively. In FIG. 11, a sunny place created by sun Bt1 inthe southeast is reproduced using sunny portion BF1 projected by secondluminaire B200. Moreover, the light emitter (light diffuser B40) offirst luminaire B100 reproduces a color and brightness of a sky at thattime. In FIG. 18, a time has passed since the state in FIG. 11, and asunny place created by sun Bt2 in the south is reproduced using sunnyportion F2 projected by second luminaire B200. Moreover, the lightemitter of first luminaire B100 reproduces a color and brightness of asky at that time. In FIG. 19, a time has passed since the state in FIG.18, and a sunny place created by sun Bt3 in the southwest is reproducedusing sunny portion F3 projected by second luminaire B200. Moreover, thelight emitter of first luminaire B100 reproduces a color and brightnessof a sky at that time.

As described above, it is possible to reproduce the changes of theenvironment in space BH due to the movement of suns Bt1, Bt2, and Bt3,by controller B330 controlling first luminaire B100 and second luminaireB200 over time.

It should be noted that a time between timings of switching may be setin such a manner that does not cause discomfort in changes of anenvironment. For example, if the state in FIG. 11 is suddenly changed tothe state in FIG. 18, the user is to feel discomfort with the amount ofchange. For this reason, an amount of change decreases with a decreasein time between timings of switching, and it is possible to achieve anenvironment change without discomfort.

Other Variations of Embodiment 2

Although illumination system B1 and the illumination control methodaccording to Embodiment 2 have been described above, the presentdisclosure is not limited to Embodiment 2.

For example, Embodiment 2 illustrates the case in which the environmentreproduction condition is created by mobile terminal B400 andtransmitted to communication unit B320 of control device B300. However,an environment reproduction condition may be created by a device otherthan mobile terminal B400. For example, controller B330 may obtain anenvironment reproduction condition by creating the environmentreproduction condition. In this case, controller B330 serves as anobtaining unit. Moreover, controller B330 may input a necessarycondition to a server device (e.g., a cloud server) that is external andcommunicable with communication unit B320 of controller B330, and theserver device may create an environment reproduction condition.

When an environment reproduction condition is created by a device otherthan mobile terminal B400, as described in Variation 5, it is possibleto control first luminaire B100 and second luminaire B200 over time.Assuming that the device other than mobile terminal B400 is controllerB330, in the first method, controller B330 creates, for each timing ofswitching, an environment reproduction condition corresponding to thetiming, and controls first luminaire B100 and second luminaire B200 eachtime controller B330 creates the environment reproduction condition. Inaddition, in the second method, controller B330 creates a time tableincluding temporal changes of an environment reproduction condition, andcontrols first luminaire B100 and second luminaire B200 based on thetime table.

Moreover, regarding the first environment reproduction condition basedon the present position of illumination system B1, for example, a colorand brightness of a sky, a position of the sun, and a color temperatureand luminance of sunlight at the present time may be calculated from animage of an area around the present position obtained by a live cameraor mobile terminal B400 etc.

Moreover, second luminaire B200 may be a luminaire other than aprojector as long as the luminaire is of a projection type. Examples ofthe luminaire other than the projector include a spotlight. When thespotlight is used as second luminaire B200, an adjustable orientation ofthe body of the spotlight makes the position of a sunny portion createdby the spotlight self-adjustable.

Moreover, when a mask is disposed in front of the spotlight in a lightemission direction, the shape of a sunny portion is reproduced by anopening of the mask. In other words, by mounting self-switchable maskshaving different opening shapes to the spotlight and switching one ofthe masks in front of the spotlight to a different one of the masks, itis possible to change the shape of the sunny portion created by thespotlight.

Moreover, although Embodiment 2 illustrates the case in which a set offirst luminaire B100 and second luminaire B200 is disposed in same spaceBH, sets of first luminaries B100 and second luminaries B200 may bedisposed in same space BH. In this case, single control device B300 maycontrol the sets of first luminaries B100 and second luminaries B200, orcontrol device B300 may be provided for each of the sets. In eithercase, it is assumed that the sets of first luminaries B100 and secondluminaries B200 are controlled based on the same environmentreproduction condition. Accordingly, since the sets of first luminariesB100 and second luminaries B200 reproduce the same environment, it ispossible to further enhance a sense of reality. Furthermore, when firstluminaries B100 are assumed to be windows and sunny portions created bysecond illumination light emitted by second luminaries B200 are assumedto be sunny places, it is also possible to further enhance a sense ofreality by disposing the sets of first luminaries B100 and secondluminaries B200 to cause positional relationships between the windowsand the sunny portions to be substantially parallel.

Moreover, the controller may control the first luminaire to cause acolor temperature of the first illumination light to correspond to acolor temperature specified by or determined from the environmentreproduction condition.

Furthermore, the controller may control the first luminaire to causeluminance of the first illumination light to correspond to luminancespecified by or determined from the environment reproduction condition.

Moreover, the controller may control the first luminaire to cause acolor temperature and luminance of the first illumination light tocorrespond to a color temperature and luminance specified by ordetermined from the environment reproduction condition.

Furthermore, the environment reproduction condition may change overtime.

Moreover, the environment reproduction condition may be renewedaccording to time.

Furthermore, the environment reproduction condition may be a presentenvironment reproduction condition based on a present position and adate and time of the illumination system.

Moreover, the environment reproduction condition may be a specified areaenvironment reproduction condition specified by a user.

Furthermore, the controller may control the first luminaire to cause thefirst luminaire to emit the first illumination light according to afirst environment reproduction condition.

Moreover, the controller may control the second luminaire to cause thesecond luminaire to emit the second illumination light according to asecond environment reproduction condition.

Embodiment 3

Conventionally, an illumination apparatus is disclosed which includes alight source that emits light and a light guide plate having a flat exitsurface through which the light from the light source exits (seeJapanese Unexamined Patent Application Publication No. 2016-12540, forexample). This illumination apparatus has minute projections andrecesses in the exit surface of the light guide plate. Even when thelight is yellowish, the projections and recesses cause the light toscatter and complement blue light, so that the exiting light achievescolor uniformity.

With such an illumination apparatus, the exiting light achieves coloruniformity by light scattering. However, when, for example, an imagethat changes with time like the sky is projected on the illuminationapparatus, a person near the illumination apparatus may feel strangedepending on the projection condition.

In view of the above, Embodiment 3 has an object to provide anillumination apparatus and related technologies capable of reducing afeeling of strangeness generated when projecting a changing image.

Hereinafter, an illumination apparatus according to Embodiment 3 will bedescribed with reference to the drawings. The illumination apparatusaccording to Embodiment 3 provides a user with a realistic feeling oflooking at the sky through a window from indoors. For example, theillumination apparatus is installed indoors, and artificially produceslight that looks like the natural sky (a blue sky or sunset, forexample) seen through a window indoors (hereinafter, such light isreferred to as artificial outdoor light).

When an image that changes like the sky is projected on the illuminationapparatus, a user near the illumination apparatus may feel strange ifthe brightness or color of the image changes drastically. Thus, theillumination apparatus according to Embodiment 3 has a configurationthat reduces the user's feeling of strangeness generated when a changingimage is projected, by keeping the change in the brightness or colorwithin a predetermined limit range, for example.

[Configuration of Illumination Apparatus]

Hereinafter, illumination apparatus C1 according to Embodiment 3 will bedescribed. FIG. 20 is a perspective view illustrating an exteriorappearance of illumination apparatus C1. FIG. 21 is a perspective viewillustrating illumination apparatus C1 installed in ceiling C70. FIG. 22is an exploded perspective view of a portion of illumination apparatusC1.

As illustrated in FIG. 20 to FIG. 22, illumination apparatus C1includes: case C10; light source C20 including light-emitting moduleC21; light reflector C30; light diffuser C40; controller C50; and powersource C60.

Light-emitting module C21 can be configured in the same manner aslight-emitting modules A20 and B20 in Embodiments 1 and 2. Further,light reflector C30 can be configured in the same manner as lightreflectors A30 and B30. Furthermore, light diffuser C40 can beconfigured in the same manner as light diffusers A40 and B40.

Case C10 is a housing body that houses light-emitting module C21, lightreflector C30, light diffuser C40, controller C50, and power source C60.

Case C10 is a flat box body, having a substantially rectangular shape ina plan view. Note that the shape of case C10 is not limited to thesubstantially rectangular shape, and case C10 may be substantiallycircular, substantially polygonal, or substantially semicircular, forexample. The shape is not particularly limited.

Case C10 includes housing portion C11 and frame portion C12.

Housing portion C11 is a flat box body that houses light-emitting moduleC21, light reflector C30, light diffuser C40, controller C50, and powersource C60. Note that controller C50 and power source C60 need not behoused in housing portion C11, and may be disposed outside case C10, forexample. Housing portion C11 has an opening (hereinafter referred to asfirst opening portion C15) in a surface (hereinafter referred to as abottom surface) of housing portion C11 on the floor side (the Z axisnegative-side), and houses light diffuser C40 to cover first openingportion C15. In other words, the size of first opening portion C15corresponds to the size of light diffuser C40. In Embodiment 3, theshape of first opening portion C15 is substantially rectangular.

Frame portion C12 is a loop-shaped (frame-shaped) member having asubstantially rectangular shape in a plan view, and is disposed at theedge of the bottom surface of housing portion C11. In other words, frameportion C12 is disposed on the bottom surface of housing portion C11 tosurround first opening portion C15 of housing portion C11. Thus, in aplan view of illumination apparatus C1, the opening of frame portion C12(hereinafter referred to as second opening portion C16) and firstopening portion C15 are substantially the same in shape. In Embodiment3, second opening portion C16 has the same, substantially rectangularshape as first opening portion C15.

The light exiting from light diffuser C40 passes through second openingportion C16. Note that the shape of frame portion C12 is not limited tothe substantially rectangular shape as long as the light exiting fromlight diffuser C40 can pass through frame portion C12. Frame portion C12may be substantially circular, substantially polygonal, or substantiallysemicircular, for example. The shape is not particularly limited. Forexample, the outline of frame portion C12 may have the same shape asthat of housing portion C11 in a plan view.

Frame portion C12 includes bottom surface C12 a and rising portion C12b. As illustrated in FIG. 21, illumination apparatus C1 is recessed inceiling C70 so that bottom surface C12 a is flush with the ceilingsurface. Rising portion C12 b is formed substantially vertical towardthe side opposite the floor (the direction on the Z axis positive side)from the end portion of bottom surface C12 a on second opening portionC16 side. Note that the ceiling surface is an example of an installationsurface of a building part.

Case C10 includes, for example, a metal material or a non-metal materialhaving high thermal conductivity. An example of the non-metal materialhaving high thermal conductivity is a resin having a high rate ofthermal conductivity (a high thermal conductive resin). Use of amaterial having high thermal conductivity for case C10 allows heatgenerated by light-emitting module C21 to be dissipated outside via caseC10. Note that housing portion C11 and frame portion C12 may includemutually different materials.

Note that housing portion C11 and frame portion C12 may be integrallyformed to make up case C10, or, housing portion C11 and frame portionC12 may be separately formed and make up case C10 by adhesion with eachother.

Light-emitting module C21 is a light source that emits light for formingan image. Light-emitting module C21 is fixed to the end portion of lightreflector C30 on the side opposite light diffuser C40 (the end portionon the Z axis positive side). Light-emitting module C21 includes boardC23 and a plurality of light-emitting elements C22 mounted on board C23.

Board C23 is a printed wiring board for mounting the plurality oflight-emitting elements C22, and is substantially rectangular in shape.For example, a resin board that mainly includes a resin, a metal-basedboard that mainly includes a metal, a ceramic board including a ceramic,etc., can be used as board C23.

Each light-emitting element C22 includes light emitting diode (LED)elements. In Embodiment 3, each light emitting element C22 is anRGB-type element that emits blue light, green light, and red light (thatis, light of three primary colors). A plurality of light-emittingelements C22 are disposed on the floor-side surface of board C23. Forexample, the plurality of light-emitting elements C22 are arranged inrows and columns on the floor-side surface of board C23. For example,the plurality of light-emitting elements C22 are equally spaced.

Note that the LED elements may be surface mount device (SMD) type LEDelements, or may be chip on board (COB) type light-emitting elements.The light emitted from each light-emitting element C22 is not limited tothe RGB three colors, and may be RGBW four colors or may be BW (blue andwhite) two colors.

Although not illustrated, disposed on board C23 are signal lines thattransmit a control signal from controller C50 and power lines thatsupply power from power source C60. For example, the signal lines andthe power lines are formed to connect the plurality of light-emittingelements C22 in series. Each light-emitting element C22 receives thesupply of power from power source C60 via the power lines, and emitspredetermined light based on the control signal received via the signallines. Since light-emitting elements C22 in Embodiment 3 are RGB typelight-emitting elements, it is possible to emit light in various colorsby controlling the emission of blue light, green light, and red light.That is to say, it is possible to emit light including an imagesimulating, for example, a blue sky, a white cloud, a cloudy sky, anevening sky, or a sunset, by controlling the light emission from eachlight emitting element C22 via controller C50.

Light reflector C30 is tubular, and is at least partially disposedbetween light-emitting module C21 and light diffuser C40. Lightreflector C30 is an optical member that reflects the light emitted fromlight-emitting module C21. Specifically, light reflector C30 reflectslight incident on the inner surface of light reflector C30 (in otherwords, the surface of light reflector C30 on light-emitting module C21side) from light-emitting module C21, toward light diffuser C40 side.The user sees a combined image of (i) an image formed by light emittedfrom light-emitting module C21 and entering light diffuser C40 withoutthrough light reflector C30 and (ii) an image formed by light emittedfrom light-emitting module C21 and entering light diffuser C40 afterbeing reflected by light reflector C30.

Light reflector C30 is formed by, for example, performing mirror surfacetreatment or diffusion treatment on a surface formed from a metalmaterial such as aluminum. The mirror surface treatment is polishing orlapping, for example. The diffusion treatment is, for example, mattingsuch as anodizing. Note that it is only necessary that the diffusiontreatment is performed on at least the inner surface of light reflectorC30. Furthermore, light reflector C30 does not necessarily have toundergo the mirror surface treatment or the diffusion treatment, and mayremain untreated by the mirror surface treatment or the diffusiontreatment.

Light diffuser C40 is an optical member which diffuses and transmits thelight entering from light-emitting module C21 side, toward the floor.Specifically, light diffuser C40 is a diffuser panel which transmits anddiffuses the light entering from a light entrance surface (the surfaceon the Z axis positive side) of light diffuser C40, and allows the lightto exit from a light exit surface of light diffuser C40.

Light diffuser C40 is a plate member that is rectangular in a plan view.Light diffuser C40 is fixed to the end portion of light reflector C30 ona side opposite light-emitting module C21 (the end portion on the Z axisnegative side). In other words, light diffuser C40 is opposed tolight-emitting module C21 and is disposed covering light-emitting moduleC21. Furthermore, light diffuser C40 is disposed covering first openingportion C15 of case C10.

Light diffuser C40 has the property of transmitting and diffusing thelight emitted from light-emitting module C21. For example, lightdiffuser C40 is manufactured by performing diffusion treatment on atransparent plate including glass or a resin material such astransparent acrylic or polyethylene terephthalate (PET). Since lightdiffuser C40 is formed from a transparent material, light diffuser C40has a high transmittance. For example, the all-light transmittance oflight diffuser C40 is 80% or greater, preferably 90% or greater.

The diffusion treatment is performed on at least one of the lightentrance surface and the light exit surface of light diffuser C40. Oneexample of the diffusion treatment is prism processing by which a prismincluding minute dot-shaped holes (recesses) is formed. The diffusiontreatment is not limited to the prism processing, and may be performedby texturing or printing.

The haze value of light diffuser C40 that has undergone the diffusiontreatment is, for example, at least 10% and at most 90%. By making thehaze value at least 10%, it is possible to inhibit light-emittingelements C22 of light-emitting module C21 from appearing as granular tothe user, even when light diffuser C40 is formed from a transparentmaterial. Moreover, by making the haze value at most 90%, it is possibleto maintain, to some extent, the outline of the image projected on lightdiffuser C40 (for example, the outline of a cloud in a blue sky). Notethat the haze value is adjustable according to the shape and size of theprism formed by the prism processing, for example.

FIG. 23 is a block diagram illustrating a control configuration ofillumination apparatus C1.

When focusing on the control configuration of illumination apparatus C1,illumination apparatus C1 includes controller C50, storage C51, andlight-emitting module C21.

Controller C50 is a control device that controls operations such asturning on and off, control of the light intensity, and control of thetone (adjustment of the light color or the color temperature) oflight-emitting module C21. Controller C50 is realized by amicrocomputer, a processor, or a specialized circuit, for example. Notethat power source C60 is a structural element included in controller C50and thus omitted in FIG. 23. Power source C60 converts AC power suppliedfrom a commercial power source into DC power at a predetermined levelthrough rectification, smoothing, and stepping-down, for example, andsupplies the DC power to light-emitting module C21.

Controller C50 obtains information on an image stored in storage C51,and controls light-emitting module C21 according to the information. Forexample, when a blue sky is to be projected on light diffuser C40,controller C50 obtains information on a blue sky from storage C51, andcontrols the light emission from the plurality of light-emittingelements C22 based on the information obtained. By the plurality oflight-emitting elements C22 emitting light, an image is projected onlight diffuser C40.

Controller C50 and light-emitting module C21 (the plurality oflight-emitting elements C22) are electrically connected via the signallines. Controller C50 outputs a control signal including information onthe brightness of the blue LED, the green LED, and the red LED to eachlight-emitting element C22 via the signal lines according to theinformation obtained from storage C51. Receiving the control signal,each light-emitting element C22 emits blue light, green light, and redlight based on the control signal.

Controller C50 outputs the control signal to light-emitting module C21at time intervals at which the motion of the image does not becomeunnatural, for example. For example, controller C50 outputs the controlsignal 20 times in about one second. This enables representation of amore natural motion when displaying an image simulating a cloud movingin a blue sky, for example.

When changing the light emission from the plurality of light-emittingelements C22 to display a changing image as described above, controllerC50 of illumination apparatus C1 controls the light emission from theplurality of light-emitting elements C22 to keep a change in at leastone of (i) the light amount, (ii) the color temperature, and (iii) thespectral distribution of light exiting from light diffuser C40 ofillumination apparatus C1 within a predetermined range. Hereinafter, animage display method performed by illumination apparatus C1 will bedescribed.

[Image Display Method Performed by Illumination Apparatus]

With reference to FIG. 24 to FIG. 27, an image display method performedby illumination apparatus C1 will be described.

FIG. 24 is a flow chart for displaying an image on illuminationapparatus C1.

First, as illustrated in FIG. 24, an image dependent on a time of day isobtained from storage C51 and displayed on light diffuser C40 (CS11).Specifically, when a producer (user) wishes to display a daytime sky,controller C50 obtains an image simulating a sky of the daytime storedin storage C51, e.g., an image including a white cloud and a blue sky,and causes the plurality of light-emitting elements C22 to emit lightbased on the image.

Next, at least a part of the image is changed to keep a predeterminedparameter of the image within a predetermined range (CS12).Specifically, controller C50 changes at least a part of the image sothat the area ratio between the white cloud and the blue sky in theimage equals the area ratio for a previously projected image (forexample, white cloud region/blue sky region=0.3). Note that controllerC50 may read from storage C51 an image which is at least partiallychanged in advance to satisfy this condition, and use this image as thechanged image.

Note that the area ratio may be defined as a ratio of the white cloudregion to the image. The area ratio may also be defined as a ratio ofthe blue sky region to the image.

The changed image is then displayed on light diffuser C40 (CS13). Next,whether or not to continue displaying the image is determined (CS14).Whether or not to continue displaying the image is determined asappropriate according to an input from the user. When it is determinedto continue displaying the image (YES in CS14), the processing returnsto CS12, and the image displayed in Step CS13 is changed to keep apredetermined parameter (the area ratio, for example) of the imagewithin a predetermined range (CS12).

By repeatedly performing Steps CS12, CS13, and CS14 in such a manner,the image is continuously displayed during a predetermined time of day.In FIG. 24, the one cycle of performing Steps CS12, CS13, and CS14 insequence and returning to Step CS12 again is the unit time of the imagedisplay performed by illumination apparatus C1. The unit time is a shortperiod of time, e.g., at least 0.001 seconds and at most 1 second, andis, for example, 0.05 seconds in Embodiment 3.

When it is determined in Step CS14 not to continue displaying the image(NO in CS14), the display of the image is finished.

The above description of the processing flow has presented a controlmethod by which the area ratio between the white cloud and the blue skyin the image is made equal to the area ratio for a previously projectedimage. As illustrated in Step CS12, the control may also be performed tokeep a predetermined parameter (the area ratio) within a certain range.

FIG. 25 illustrates the amount of light of images projected onillumination apparatus C1. (a) and (b) of FIG. 25 illustrate thedifference in the amount of light exiting from light diffuser C40 in theform of dot gradation.

(a) of FIG. 25 is an image projected on light diffuser C40 at aparticular time, and shows one large white cloud with a blue sky in thebackground. (b) of FIG. 25 is an image projected on light diffuser C40after a predetermined time period has passed from (a), and shows threesmall white clouds with a blue sky in the background. (b) of FIG. 25 isan image after five minutes have passed from (a), for example.

In Embodiment 3, controller C50 changes at least a part of the image tokeep a change in the amount of light exiting from light diffuser C40within a predetermined range. For example, controller C50 may change atleast a part of the image so that a ratio of the white cloud region tothe image as a whole in (a) of FIG. 25 and a ratio of the white cloudregion to the image as a whole in (b) of FIG. 25 become substantiallyequal. Further, controller C50 may change at least a part of the imageso that a ratio of the blue sky region to the image as a whole in (a) ofFIG. 25 and a ratio of the blue sky region to the image as a whole in(b) of FIG. 25 become substantially equal. For example, controller C50may change at least a part of the image so that the area ratio betweenthe white cloud region and the blue sky region in (a) of FIG. 25 and thearea ratio between the white cloud region and the blue sky region in (b)of FIG. 25 become substantially equal. When doing so, for example,controller C50 may change at least a part of the image so that both ofthese area ratios between the white cloud region and the blue sky regionbecome at least 0.2 and at most 0.4. This allows the change in theamount of light exiting from light diffuser C40 to be kept within apredetermined range. The area of each of the white cloud region and theblue sky region projected on light diffuser C40 can be derived by, forexample, binarizing the image projected on light diffuser C40 accordingto the color, i.e., white and blue.

In such a manner, when changing the image, i.e., when changing the lightemission from light-emitting elements C22, controller C50 performscontrol to keep a change in the amount of light exiting from lightdiffuser C40 within a predetermined range. This makes it possible toreduce the feeling of strangeness generated when the changing image isprojected on illumination apparatus C1. If a change in the amount oflight emitted from an illumination apparatus projecting a changing imageis large, a person in the space illuminated with the light from theillumination apparatus may feel strange due to the change in the amountof light. With the configuration according to Embodiment 3, however,such a feeling of strangeness can be reduced.

FIG. 26 illustrates the color temperature of images projected onillumination apparatus C1. The images in (a) and (b) of FIG. 26correspond to the images in (a) and (b) of FIG. 25, respectively, andthe difference in color temperature of light exiting from light diffuserC40 is indicated by the difference in hatching width.

As illustrated in FIG. 26, when changing the image, i.e., when changingthe light emission from light-emitting elements C22, controller C50 ofillumination apparatus C1 performs control to keep a change in the colortemperature of light exiting from light diffuser C40 within apredetermined range. This makes it possible to reduce the feeling ofstrangeness generated when an image is projected on illuminationapparatus C1. For example, when the color temperature suddenly changesfrom 5500 K equivalent to white to several tens of thousands of K orgreater equivalent to blue, the illuminated object suddenly looks blue,causing the user to have a feeling of strangeness. To overcome this, thelight emission from light-emitting elements C22 is controlled to keepthe change in the color temperature within a predetermined range likethe change from the state in (a) of FIG. 26 to the state in (b) of FIG.26, so that the user's feeling of strangeness can be reduced.

FIG. 27 illustrates another example of images projected on illuminationapparatus C1. (a) and (b) of FIG. 27 illustrate the difference in theamount of light exiting from light diffuser C40 in the form of dotgradation.

(a) of FIG. 27 is an image projected on light diffuser C40 at aparticular time, and shows one large white cloud with a blue sky in thebackground. (b) of FIG. 27 is an image projected on light diffuser C40after a predetermined time period has passed from (a), no longer showingthe white cloud or blue sky but a cloudy sky. (b) of FIG. 27 is an imageafter 10 minutes have passed from (a), for example.

In the example illustrated in FIG. 27, controller C50 changes at least apart of the image to keep a change in the light flux ratio between whitelight and blue light projected on light diffuser C40 within apredetermined range. Specifically, controller C50 changes at least apart of the image so that the light flux ratio between the white lightand the blue light in (a) of FIG. 27 and the light flux ratio betweenthe white light and the blue light in (b) of FIG. 27 becomesubstantially equal. This makes it possible to keep the change in theamount of light exiting from light diffuser C40 within a predeterminedrange, and reduce the feeling of strangeness generated when the changingimage is projected on illumination apparatus C1. Note that the lightflux of the white light and the light flux of the blue light in theimage simulating the cloudy sky can be derived by, for example,extracting the white light component and the blue light component in theimage simulating the cloudy sky.

[Advantageous Effects Etc.]

Illumination apparatus C1 according to Embodiment 3 includes: case C10having opening portion C15; light source C20 disposed in case C10, lightsource C20 including a plurality of light-emitting elements C22; lightdiffuser C40 which is disposed in opening portion C15, and diffuses andtransmits light emitted from the plurality of light-emitting elementsC22; and controller C50 that controls light emission from light sourceC20. Controller C50: controls light emission from the plurality oflight-emitting elements C22 to project an image on light diffuser C40,the image changing with time; and when changing the light emission fromthe plurality of light-emitting elements C22 changing the image,controls the light emission from light source C20 to keep a change in atleast one of (i) a light amount, (ii) a color temperature, and (iii) aspectral distribution of light emitted from illumination apparatus 1Cwithin a predetermined range.

In such a manner, when changing an image based on the light emissionfrom light-emitting elements C22, it is possible to reduce the feelingof strangeness generated when the image (the changing image) isprojected on illumination apparatus C1, by controlling the lightemission from light source C20 to keep the change in the amount of lightemitted from illumination apparatus C1 within a predetermined range.Furthermore, it is possible to reduce the feeling of strangenessgenerated when the image is projected on illumination apparatus C1, byperforming control to keep the change in the color temperature of lightemitted from illumination apparatus C1 within a predetermined range.That is to say, illumination apparatus C1 makes it possible to reducethe strangeness felt by a person present in the space illuminated withthe light from illumination apparatus C1 projecting the changing image.

Note that although the above description has presented the case wherecontrol is performed to keep the change in the light amount or colortemperature of light within a predetermined range, the presentdisclosure is not limited to this case. The light emission from lightsource C20 may be controlled to keep a change in the spectraldistribution of light within a predetermined range. That is to say, whenchanging the light emission from the plurality of light-emittingelements C22, controller C50 may control the light emission from lightsource C20 to keep a change in at least one of (i) the light amount,(ii) the color temperature, and (iii) the spectral distribution of lightemitted from illumination apparatus C1 within a predetermined range.

Further, as the control of the light emission from light source C20described above, when changing the light emission from the plurality oflight-emitting elements C22, controller C50 may control the lightemission from light source C20 to keep a change in at least one of (i)the light amount and (ii) the color temperature of light exiting fromlight diffuser C40 of illumination apparatus C1 within a predeterminedrange.

In such a manner, when changing an image based on the light emissionfrom light-emitting elements C22, it is possible to reduce the feelingof strangeness generated when the image (the changing image) isprojected on illumination apparatus C1, by controlling the lightemission from light source C20 to keep the change in the amount of lightexiting from light diffuser C40 within a predetermined range.Furthermore, it is possible to reduce the feeling of strangenessgenerated when the image is projected on illumination apparatus C1, byperforming control to keep the change in the color temperature of lightexiting from light diffuser C40 within a predetermined range.

Controller C50 may change at least a part of the image to keep a changein at least one of (i) the light amount and (ii) the color temperatureof the light within the predetermined range.

In such a manner, it is possible to reduce the feeling of strangenessgenerated when the changing image is projected on illumination apparatusC1, by changing at least a part of the image to keep the change in thelight amount or color temperature of light exiting from light diffuserC40 within a predetermined range.

When the image is an image simulating a cloud and a blue sky, controllerC50 may change at least a part of the image to keep at least one of achange in the ratio of a cloud region to the image as a whole and achange in the ratio of a blue sky region to the image as a whole withina predetermined range. Here, the cloud region is a region of the cloud,and the blue sky region is a region of the blue sky.

In such a manner, it is possible to keep the light amount or colortemperature of the sum of light emitted from illumination apparatus C1within a predetermined range, by changing at least a part of the imageto keep a change in the above ratio within a predetermined range. Thismakes it possible to reduce the feeling of strangeness generated whenthe changing image is projected on illumination apparatus C1.

When the image is projected using white light and blue light, controllerC50 may change at least a part of the image to keep a change in thelight flux ratio within a predetermined range.

In such a manner, it is possible to keep the light amount or colortemperature of light emitted from illumination apparatus C1 within apredetermined range, by changing at least a part of the image to keep,for example, the light flux ratio between the white light and the bluelight within a predetermined range. This makes it possible to reduce thefeeling of strangeness generated when the changing image is projected onillumination apparatus C1. In order to keep the amount of light emittedfrom illumination apparatus C1 within a predetermined range, control maybe performed to keep the amount of light emitted from eachlight-emitting element C22 within a predetermined range, or, control maybe performed to keep the light amount of the sum of light emitted fromillumination apparatus C1 within a predetermined range. Whensignificantly changing the brightness and color of light emitted fromeach light-emitting element C22, control is performed to keep the sum oflight emitted from illumination apparatus C1 within a predeterminedrange.

Controller C50 may keep a change in at least one of (i) the lightamount, (ii) the color temperature, and (iii) the spectral distributionof the light within the predetermined range during a unit time.

This makes it possible to reduce the feeling of strangeness aboutillumination apparatus C1 during a determined unit time. For example,when the unit time is determined to be at least 0.001 seconds and atmost 1 second, it is possible to reduce the feeling of strangeness aboutillumination apparatus C1 during this short period of time.

Controller C50 may control the light emission from light source C20 tokeep a change in at least one of (i) the light amount, (ii) the colortemperature, and (iii) the spectral distribution of the light emittedfrom illumination apparatus C1 within the predetermined range during apredetermined time of day. The predetermined time of day may be arounddawn, in morning, daytime, in evening, or around dusk. Around dawn maybe a time during an hour before and after sunrise. Around dusk may be atime during an hour before and after sunset.

This makes it possible to reduce the feeling of strangeness aboutillumination apparatus C1 during a predetermined time of day. Forexample, when a day is divided into morning, daytime, evening, andnight, and the daytime is determined as the predetermined time of day,it is possible to reduce the feeling of strangeness about illuminationapparatus C1 during the daytime. That is to say, controller C50 maycontrol the light emission from light source C20 to keep a change in atleast one of (i) the light amount, (ii) the color temperature, and (iii)the spectral distribution of the light emitted from illuminationapparatus C1 within a predetermined range during a time of dawn,morning, daytime, or evening.

(Variation 6)

[Configuration of Illumination Apparatus]

Next, illumination apparatus C1A according to Variation 6 will bedescribed. Illumination apparatus C1A according to Variation 6 includesa plurality of light-emitting sources C26 different from light-emittingmodule C21, in addition to the structural elements of illuminationapparatus C1 according to Embodiment 3.

FIG. 28 is a perspective view illustrating illumination apparatus C1Ainstalled in ceiling C70. FIG. 29 is a block diagram illustrating acontrol configuration of illumination apparatus C1A.

As illustrated in FIG. 28, illumination apparatus C1A includes: caseC10; light source C20 including light-emitting module C21 and theplurality of light-emitting sources C26; light reflector C30; lightdiffuser C40; controller C50; and power source C60. Light-emittingmodule C21, light reflector C30, light diffuser C40, controller C50, andpower source C60 of illumination apparatus C1A have a configurationsubstantially the same as that of illumination apparatus C1 described inEmbodiment 3 above. Thus, the description thereof will be omitted.

Case C10 of illumination apparatus C1A includes housing portion C11 andframe portion C12. Bottom surface C12 a of frame portion C12 is widerthan bottom surface C12 a according to Embodiment 3 described above. Inthe present variation, a plurality of indentations (recesses) are formedin this wide bottom surface C12 a, and the plurality of light-emittingsources C26 are recessed in the indentations.

The plurality of light-emitting sources C26 are disposed outside secondopening portion C16 to surround second opening portion C16 in a planview. Each light-emitting source C26 is, for example, a downlightincluding a light-emitting element and an opening cover. As illustratedin FIG. 29, the plurality of light-emitting sources C26 are connected tocontroller C50.

Controller C50 controls light emission from light-emitting module C21and light emission from the plurality of light-emitting sources C26.Specifically, when changing the light emission from light-emittingmodule C21, controller C50 of illumination apparatus C1A controls thelight emission from the plurality of light-emitting sources C26 to keepthe change in the light amount, color temperature, or spectraldistribution of light exiting from illumination apparatus C1A within apredetermined range.

[Image Display Method performed by Illumination Apparatus]

FIG. 30 is a flow chart for displaying an image on illuminationapparatus C1A.

First, an image dependent on a time of day is obtained from storage C51(CS21). For example, controller C50 obtains an image simulating a sky ofthe daytime stored in storage C51, e.g., an image including a whitecloud and a blue sky.

Next, light to be emitted by the plurality of light-emitting elementsC22 for projecting an image is calculated (CS22). Specifically,controller C50 computes the amount and color temperature of light to beemitted by light-emitting elements C22, based on an image signalobtained from storage C51.

Next, the amount and color temperature of light to be emitted by theplurality of light-emitting sources C26 are determined according to thecalculated light to be emitted by light-emitting elements C22 (C523).Controller C50 determines the amount and color temperature of light insuch a manner that the amount and color temperature of light to beemitted from illumination apparatus C1A as a whole fall within apredetermined range. That is to say, the determination is made based onthe light amount and color temperature of light to be emitted by bothlight-emitting module C21 and the plurality of light-emitting sourcesC26 making up light source C20.

Then, light-emitting elements C22 emit light and project an image, andthe plurality of light-emitting sources C26 emit light based on thedetermined amount and color temperature of light (C524). Next, whetheror not to continue displaying an image is determined (C525). Whether ornot to continue displaying an image is determined as appropriateaccording to an input from the user. When it is determined to continuedisplaying an image (YES in CS25), the processing returns to Step CS21,and a new, next image is obtained (CS21).

Note that in the case of obtaining an image in Step CS21, the actualenvironmental light may be obtained from a separately provided opticalsensor, and the amount and color temperature of light may be derivedbased on the environmental light.

By repeatedly performing Steps CS21 to CS25 in such a manner, an imageis continuously displayed during a predetermined time of day. In FIG.30, the one cycle of performing Steps CS21 to CS25 in sequence andreturning to Step CS21 again is the unit time of the image displayperformed by illumination apparatus C1A. The unit time is a short periodof time, e.g., at least 0.001 seconds and at most 1 second.

When it is determined not to continue displaying an image in Step CS25(NO in CS25), the display of the image is finished.

FIG. 31 illustrates the amount of light of images projected onillumination apparatus C1A. (a) and (b) of FIG. 31 illustrate thedifference in the amount of light exiting from light diffuser C40 in theform of dot gradation. On the lower side of (a) and (b) of FIG. 31,spectral distribution charts of the light exiting from light diffuserC40 are shown.

(a) of FIG. 31 is an image projected on light diffuser C40 at aparticular time, and shows one small white cloud with a blue sky in thebackground. In the spectral distribution chart, as for light diffuserC40, the spectral intensity corresponding to the wavelengths for blue ishigh since the blue sky region is large, and as for the plurality oflight-emitting sources C26, the spectral intensity corresponding to thewavelengths for red is high since the plurality of light-emittingsources C26 are emitting bright light. (b) of FIG. 31 is an imageprojected on light diffuser C40 after a predetermined time period haspassed from (a), and shows one large white cloud, two small whiteclouds, and a blue sky in the background. In the spectral distributionchart, as for light diffuser C40, the spectral intensity correspondingto the wavelengths for yellow or red has increased since the white cloudregion has increased, and as for the plurality of light-emitting sourcesC26, the spectral intensity corresponding to the wavelengths for red hasdecreased since the plurality of light-emitting sources C26 are emittingdark light.

When changing the state in (a) of FIG. 31 to the state in (b) of FIG.31, controller C50 according to the present variation controls the lightemission from the plurality of light-emitting sources C26 to keep thechange in the spectral distribution of light emitted from illuminationapparatus C1A within a predetermined range. Specifically, in thespectral distribution charts in (a) and (b) of FIG. 31, controller C50controls the light emission from the plurality of light-emitting sourcesC26 so that a sum (the dashedline in the spectral distribution charts)of the intensity of light exiting from light diffuser C40 and theintensity of light emitted from the plurality of light-emitting sourcesC26 is substantially equal between (a) and (b). In other words,controller C50 controls the light intensity of the plurality oflight-emitting sources C26 according to the amount of light exiting fromlight diffuser C40, and controls the tone of the plurality oflight-emitting sources C26 according to the color of light exiting fromlight diffuser C40. In such a manner, the feeling of strangenessgenerated when the changing image is projected on illumination apparatusC1 is reduced by keeping the change in the spectral distribution oflight emitted from illumination apparatus C1A within a predeterminedrange.

[Advantageous Effects Etc.]

Illumination apparatus C1A according to the present variation includes:case C10 having opening portion C15; light source C20 disposed in caseC10 and including a plurality of light-emitting elements C22 and aplurality of light-emitting sources C26 different from the plurality oflight-emitting elements C22; light diffuser C40 which is disposed inopening portion C15, and diffuses and transmits light emitted from theplurality of light-emitting elements C22; and controller C50 thatcontrols light emission from the plurality of light-emitting elementsC22 and light emission from the plurality of light-emitting sources C26.Controller C50: controls the light emission from the plurality oflight-emitting elements C22 to project an image on light diffuser C40,the image changing with time; and when changing the light emission fromthe plurality of light-emitting elements C22 changing the image,controller C50 controls light emission from the plurality oflight-emitting sources C26 to keep a change in the spectral distributionof the light emitted from illumination apparatus C1A within apredetermined range.

In such a manner, when changing the image based on the light emissionfrom light-emitting elements C22, it is possible to reduce the feelingof strangeness generated when the image (the changing image) isprojected on illumination apparatus C1A, by controlling the plurality oflight-emitting sources C26 to keep the change in the spectraldistribution of light emitted from illumination apparatus C1A within apredetermined range. Furthermore, having light-emitting sources C26different from light-emitting elements C22 makes it possible to producea free image without placing restrictions on the image.

Note that although the above description has presented the case wherethe light emission from the plurality of light-emitting sources C26 iscontrolled to keep the change in the spectral distribution of lightwithin a predetermined range, the present disclosure is not limited tothis case. The light emission from the plurality of light-emittingsources C26 may be controlled to keep the change in the amount and colortemperature of light within a predetermined range. That is to say, whenchanging the light emission from the plurality of light-emittingelements C22, controller C50 may control light emission from theplurality of light-emitting sources C26 to keep a change in at least oneof (i) the light amount, (ii) the color temperature, and (iii) thespectral distribution of the light emitted from illumination apparatusC1A within the predetermined range.

Controller C50 may control the light intensity of the plurality oflight-emitting sources C26 according to the amount of light exiting fromlight diffuser C40, or may control the tone of the plurality oflight-emitting sources C26 according to the color of the light exitingfrom light diffuser C40.

In such a manner, it is possible to reduce the feeling of strangenessgenerated when the changing image is projected on illumination apparatusC1A, by controlling the light intensity or tone of the plurality oflight-emitting sources C26 via controller C50.

Further, controller C50 may control at least one of a light intensityand a tone of the plurality of light-emitting sources C26 according to achange of the image.

Note that controller C50 may derive the amount or color of the lightbased on the value of current supplied to light-emitting elements C22,may derive the amount or color of the light by detecting the currentsupplied to light-emitting elements C22, or may detect the amount orcolor of the light using an optical sensor provided externally.

(Variation 7)

Next, illumination system C2 according to another variation (Variation7) of Embodiment 3 will be described. In illumination system C2according to Variation 7, light-emitting sources C26 of illuminationapparatus C1A in Variation 6 are installed in ceiling C70.

FIG. 32 is a perspective view illustrating illumination system C2according to Variation 7. FIG. 33 is a block diagram illustrating acontrol configuration of illumination system C2 according to Variation7.

As illustrated in FIG. 32 and FIG. 33, illumination system C2 includes:illumination apparatus C1 in Embodiment 3 described above;light-emitting equipment C25 including light-emitting sources C26different from light-emitting elements C22 of illumination apparatus C1;and illumination controller C55 that controls light emission fromillumination apparatus C1 and light emission from light-emittingequipment C25.

In illumination system C2, indentations (recesses) are formed in ceilingC70, and light-emitting equipment C25 is recessed in each of theseindentations. Light-emitting equipment C25 can be also referred to as aluminaire or an illumination apparatus.

Light-emitting equipment C25 includes a plurality of light-emittingsources C26. The plurality of light-emitting sources C26 are disposedoutside second opening portion C16. Each light-emitting source C26 is,for example, an LED bulb including a light-emitting element. Asillustrated in FIG. 33, light-emitting equipment C25 is connected toillumination controller C55.

Illumination controller C55 controls the light emission fromlight-emitting module C21 and the light emission from light-emittingequipment C25. More specifically, illumination controller C55: controlsthe light emission from the plurality of light-emitting elements C22 toproject, on light diffuser C40, an image that changes with time; andwhen changing the light emission from the plurality of light-emittingelements C22, controls the light emission from light-emitting equipmentC25 to keep a change in at least one of (i) the light amount, (ii) thecolor temperature, and (iii) the spectral distribution of light emittedfrom illumination system C2 within a predetermined range. This makes itpossible to reduce the feeling of strangeness generated when thechanging image is projected on illumination apparatus C1.

Note that the number of illumination apparatuses 1 in illuminationsystem C2 is not limited to one, and two or more illuminationapparatuses 1 may be provided. For example, illumination system C2 mayhave such a configuration that, when each illumination apparatus C1outputs a different image, the feeling of strangeness about the lightilluminating the space as a whole is reduced by controlling theintensity or color of light emitted from light-emitting equipment C25.

Other Variations of Embodiment 3

Hereinbefore, the present disclosure has been described based onEmbodiment 3; however, the present disclosure is not limited toEmbodiment 3.

Embodiment 3 etc. have presented the example where an image simulating awhite cloud and a blue sky is projected on light diffuser C40; however,the image is not limited to this example. For example, as illustrated in(a) and (b) of FIG. 34, an image simulating a sunset and an evening skymay be projected on light diffuser C40. In this case too, when changingthe light emission from the plurality of light-emitting elements C22,light emission from light source C20 is controlled to keep a change inat least one of (i) the light amount, (ii) the color temperature, and(iii) the spectral distribution of the light emitted from illuminationapparatus C1, C1A, or illumination system C2 within a predeterminedrange. This makes it possible to reduce the feeling of strangenessgenerated when an image is projected on illumination apparatus C1, C1Aor illumination system C2.

Further, although Embodiment 3 etc. have illustrated the example wherecase C10 includes frame portion C12, the present disclosure is notlimited to this example. For example, frame portion C12 may beconfigured as a portion of a building part.

Furthermore, although Embodiment 3 etc. have illustrated the examplewhere illumination apparatus C1 or C1A is recessed in ceiling C70, thepresent disclosure is not limited to this example. For instance,illumination apparatus C1 or C1A may be recessed in a wall, for example.In this case, the wall is an example of a building part.

Furthermore, although Embodiment 3 etc. have presented the example wherelight diffuser C40 is manufactured by performing diffusion treatment ona transparent plate (for example, a transparent acrylic plate), thepresent disclosure is not limited to this example. For example, lightdiffuser C40 may be prepared by providing a diffusion sheet on atransparent plate. In this case, it is only necessary that a diffusionsheet is provided on at least one surface of the transparent plate,i.e., either the surface on the floor side or the surface onlight-emitting module C21 side. In addition, light diffuser C40 may be amilky white diffuser having a light diffusing material (for example,light-reflective microparticles such as silica particles) dispersedtherein. Such a diffuser is manufactured by resin molding, into apredetermined shape, a light-transmissive resin material having a lightdiffusing material mixed therein. Note that although the color of lightdiffuser C40 may be milky white, light diffuser C40 may be, for example,a transparent resin material on which diffusion treatment is performed,in a viewpoint of reducing light loss.

As described above, according to Embodiment 3 etc., in a spaceilluminated with light emitted from an illumination apparatus in such agreat amount that the emitted light substantially controls thebrightness of the space, it is possible to reduce the strangeness that aperson in the space (user) feels (i) when the appearance of an object inthe space significantly changes due to a change in the color orintensity of light of an image or due to a change in the spectralwavelength characteristics of the spatial light or (ii) when asignificant departure occurs from spatial light black body radiation.

For example, illumination apparatus C1 according to Embodiment 3includes: case C10 having opening portion C15; light source C20 disposedin case C10 and including a plurality of light-emitting elements C22;light diffuser C40 which is disposed in opening portion C15, anddiffuses and transmits light emitted from the plurality oflight-emitting elements C22; and controller C50 that controls lightemission from light source C20. Controller C50: controls light emissionfrom the plurality of light-emitting elements C22 to project an image onlight diffuser C40, the image changing with time; and when changing thelight emission from the plurality of light-emitting elements C22changing the image, controls the light emission from light source C20 tokeep a change in the amount of light exiting from light diffuser C40 ofillumination apparatus C1 within a predetermined range during a unittime.

For example, controller C50 may: control the light emission from theplurality of light-emitting elements C22 to project an image on lightdiffuser C40, the image changing with time; and when changing the lightemission from the plurality of light-emitting elements C22, control thelight emission from light source C20 to keep a change in the colortemperature of the light exiting from light diffuser C40 of illuminationapparatus C1 within a predetermined range during the unit time.

For example, controller C50 may: control the light emission from theplurality of light-emitting elements C22 to project an image on lightdiffuser C40, the image changing with time; and when changing the lightemission from the plurality of light-emitting elements C22, control thelight emission from light source C20 to keep a change in the spectraldistribution of the light exiting from light diffuser C40 ofillumination apparatus C1 within a predetermined range during the unittime.

For example, the unit time may be at least 0.001 seconds and at most 1second.

For example, an illumination apparatus according to an aspect of thepresent disclosure may be an illumination apparatus including: a casehaving an opening portion; a first light source including a plurality oflight-emitting elements disposed in the case; a second light sourcedifferent from the first light source and disposed outside the case; alight diffuser which is disposed in the opening portion, and diffusesand transmits light emitted from the plurality of light-emittingelements; and a controller that controls light emission from the firstlight source and light emission from the second light source. Thecontroller: may control light emission from the plurality oflight-emitting elements to project an image simulating a sky on thelight diffuser, the image changing with time; and when changing theimage, control the light emission from at least one of the first lightsource and the second light source to keep a change in at least one of(i) a light amount, (ii) a color temperature, and (iii) a spectraldistribution of light emitted from the illumination apparatus within apredetermined range.

Note that controller C50 may be configured to have the functions of atleast one of controllers A50 and B50.

Embodiment 4

Conventionally, an illumination apparatus that simulates natural lighthas been known. As an example of such kind of illumination apparatuses,Japanese Unexamined Patent Application Publication No. 2015-207554discloses an illumination apparatus including a light source that emitsnon-diffusing light having directivity, a light diffuser (a diffuserpanel) that diffuses light, and an inner wall surface (a side wall) thatis irradiated with light. This illumination apparatus irradiates theinner wall surface with light by diffusing, using the light diffuser,the non-diffusing light emitted from the light source, and partiallytransmitting the non-diffusing light without diffusion.

For example, with a skylight, which is a window placed at a positiondeeper than a ceiling that is a part of a building, an inner wallsurface is formed to connect the ceiling surface and the window in thedirection intersecting the ceiling surface. In general, the look of thesky etc. seen through the skylight does not appear on the inner wallsurface since natural light enters through the skylight. Theillumination apparatus disclosed in Japanese Unexamined PatentApplication Publication No. 2015-207554, however, emits artificiallight, and thus, when, for example, light having a color is projected onthe light diffuser, the inner wall surface is also irradiated with thelight having the color. As a result, a user of the illuminationapparatus may feel strange.

In view of the above, Embodiment 4 has an object to reduce a feeling ofstrangeness generated due to light irradiation of an inner wall surfaceof a part of a building or an inner wall surface of an illuminationapparatus.

[Configuration of Illumination Apparatus]

First, a schematic configuration of illumination apparatus D1 accordingto Embodiment 4 will be described.

FIG. 35 is a perspective view illustrating an exterior appearance ofillumination apparatus D1. FIG. 36 is a perspective view illustratingillumination apparatus D1 installed in ceiling D80. FIG. 37 is anexploded perspective view of portions of illumination apparatus D1. FIG.38 is a cross sectional view of the illumination apparatus illustratedin FIG. 36, taken along line XXXVIII-XXXVIII.

Illumination apparatus D1 provides a user with a realistic feeling oflooking at the sky through a window from indoors. As illustrated in FIG.36, for example, illumination apparatus D1 is installed in ceiling D80etc., that is an example of a part of a building, and projects lightsimulating a natural sky, such as a blue sky or a sunset, on lightdiffuser D40.

In the case of installing illumination apparatus D1 in ceiling D80,light diffuser D40 is disposed at a position deeper than the ceilingsurface, and thus, inner wall surface Dw1 connecting the ceiling surfaceand light diffuser D40 in the direction intersecting the ceiling surfaceis formed between the ceiling surface and light diffuser D40.Illumination apparatus D1 according to Embodiment 4 includes lightemission component D50 at a position corresponding to inner wall surfaceDw1 and causes light emission component D50 to radiate light, thusinhibiting light from light diffuser D40 from appearing on inner wallsurface Dw1, that is, light emission component D50.

Hereinafter, each structural element of illumination apparatus D1 willbe described.

As illustrated in FIG. 35 to FIG. 37, illumination apparatus D1 includescase D10, first light source D20, light diffuser D40, light emissioncomponent D50, second light source D60, and controller D70.

Case D10 can be configured in the same manner as cases A10, B10, andC10. First light source D20 can be configured in the same manner aslight-emitting modules A20, B20, and C21. Light diffuser D40 can beconfigured in the same manner as light diffusers A10, B30, and C30.

Case D10 has a rectangular parallelepiped shape, and is approximatelyrectangular in a plan view. Case D10 houses first light source D20 andlight diffuser D40. Case D10 has rectangular opening portion D11 on thefloor surface side (on the Z axis negative side). Light diffuser D40 isdisposed in opening portion D11 of case D10. Light emission componentD50 and second light source D60 are disposed on the floor surface sideof case D10. Controller D70 is disposed outside case D10. Note thatcontroller D70 may be housed in case D10.

Case D10 includes, for example, a metal material or a non-metal materialhaving excellent thermal conductive properties. An example of thenon-metal material having excellent thermal conductive properties is aresin having a high thermal conductivity. The shape of case D10 is notlimited to approximately rectangular, and may be, for example,approximately circular, approximately polygonal, or approximatelysemicircular.

First light source D20 is a light-emitting module including board D23and a plurality of light-emitting elements D22 mounted on board D23. Ascontroller D70 performs illumination control on the plurality oflight-emitting elements D22, first light source D20 emits light havingan image of a blue sky, for example.

Board D23 is a printed wiring board for mounting thereon the pluralityof light-emitting elements D22, and is approximately rectangular inshape. For example, a resin board that mainly includes a resin, ametal-based board that mainly includes a metal, a ceramic board made ofa ceramic, etc., can be used as board D23.

Each light-emitting element D22 includes light emitting diode (LED)elements. The plurality of light-emitting elements D22 are arranged inrows and columns at equal spaces on board D23. Each light-emittingelement D22 is disposed on, of the two main surfaces of board D23, amain surface opposed to light diffuser D40. In other words, first lightsource D20 is disposed such that the plurality of light-emittingelements D22 face light diffuser D40.

Each light-emitting element D22 is an RGB element that emits blue light,green light, and red light, that is, light of three primary colors.Since each light-emitting element D22 is an RGB element, it is possibleto emit light in various colors by controlling the emission of bluelight, green light, and red light. Light-emitting elements D22 may besurface mount device (SMD) elements, or may be chip on board (COB)elements.

For example, light diffuser D40 is manufactured by performing diffusiontreatment on a transparent plate including glass or a resin materialsuch as transparent acrylic, a polycarbonate resin, or polyethyleneterephthalate (PET). In the case of a resin material, the resin materialmay contain a material having light diffusion properties. The diffusiontreatment is performed on at least one of light entrance surface D41 andlight exit surface D42 of light diffuser D40. One example of thediffusion treatment is prism processing by which a prism includingminute dot-shaped holes (recesses) is formed. The diffusion treatment isnot limited to the prism processing, and may be performed by texturingor printing.

Light diffuser D40 is an optical member which transmits and diffuseslight emitted from first light source D20, and from which thetransmitted light and the diffused light exit toward the floor surfaceside. Specifically, light diffuser D40 receives, through light entrancesurface D41, the light emitted from first light source D20, andtransmits and diffuses the received light. The transmitted light and thediffused light exit from light diffuser D40 through light exit surfaceD42. Light diffuser D40 has, on light exit surface D42 side, rectangularlight exit region D43 through which the diffused light exits.

Illumination apparatus D1 in Embodiment 4 adopts light diffuser D40 sothat, when the user sees an image projected on illumination apparatusD1, the depth of the image appears easily. For example, light diffuserD40 located closer to the user allows the light emitted from lightsource D20 located farther from the user to exit in a blurred manner.With this, illumination apparatus D1 allows easy appearance of the depthof the projected image.

As illustrated in FIG. 38, light diffuser D40 is disposed such that anouter edge portion of light diffuser D40 is in contact with openingportion D11 of case D10 to block opening portion D11 of case D10.Further, light diffuser D40 is disposed at a position where light exitsurface D42 and edge surface D12 of opening portion D11 are flush witheach other so as not to expose inner surface D13 of case D10 from lightexit surface D42 toward the floor surface. Note that light diffuser D40may be attached to case D10 such that light exit surface D42 is locatedcloser to the floor surface than edge surface D12 is.

As described above, light emission component D50 and second light sourceD60 are disposed on the floor surface side of case D10.

Second light source D60 is a light emission source that emits lighttoward light emission component D50 to cause light emission componentD50 to radiate light.

Second light source D60 is disposed on edge surface D12 of case D10.Second light source D60 is an LED line module including board D63 and aplurality of light-emitting elements D62 mounted on board D63.

Board D63 is a printed wiring board for mounting thereon the pluralityof light-emitting elements D62. Board D63 is long and narrow, andapproximately rectangular in shape. For example, a resin board thatmainly includes a resin, a metal-based board that mainly includes ametal, a ceramic board made of a ceramic, etc., can be used as boardD63.

Each light-emitting element D62 includes LED elements. The plurality oflight-emitting elements D62 are arranged in a line at equal spaces onboard D63. Second light source D60 is fixed to edge surface D12 of caseD10 such that the plurality of light-emitting elements D62 face lightemission component D50.

Each light-emitting element D62 is an RGB element that emits light ofthree primary colors. Since each light-emitting elements D62 is an RGBelement, it is possible to emit light in various colors by controllingthe emission of blue light, green light, and red light. Light-emittingelements D62 may be SMD elements, or may be COB elements.

Light emission component D50 is a light guide plate which is of an edgelight type and has light emission surface D52 from which light isradiated. Light emission component D50 is disposed on light exit surfaceD42 side of light diffuser D40 in a direction orthogonal to lightdiffuser D40. Light emission component D50 is disposed outside lightexit region D43 in a direction along light exit surface D42.Illumination apparatus D1 in Embodiment 4 includes four light emissioncomponents D50. Four light emission components D50 are disposed aroundrectangular light exit region D43 to correspond to the four sides oflight exit region D43. Each light emission component D50 is disposedsuch that light emission surface D52 intersects light exit surface D42of light diffuser D40 and faces the inside of light exit region D43opposite the outside of light exit region D43.

Light emission component D50 includes: outer surface D53 opposite lightemission surface D52; upper surface D54 located on the side where edgesurface D12 of opening portion of case D10 is provided; and bottomsurface D55 located on the floor surface side opposite the side whereupper surface D54 is disposed. Recess D56 is formed in upper surfaceD54. Light emission component D50 is attached to edge surface D12 ofcase D10 with the above-described second light source housed in recessD56. Light emission component D50 is fixed to case D10 by adhesion orscrewing, for example. Light emission component D50 receives, throughupper surface D54, the light emitted from second light source D60, andradiates light from light emission surface D52 via the light guideplate.

Light emission component D50 is formed using, for example, a glassmaterial or a resin material such as an acrylic or polycarbonate resinor PET. Light emission component D50 may be transparent or may benon-transparent. A matrix of recesses or projections may be formed inlight emission surface D52 by printing etc.

Illumination apparatus D1 is installed in ceiling D80 such that bottomsurface D55 of light emission component D50 is flush with (lies in thesame surface as) the ceiling surface. Bottom surface D55 is formed inthe same color as the color of the ceiling surface by attaching a clothor by painting. Illumination apparatus D1 is installed such that outersurface D53 of light emission component D50 is in contact with the sidesurface of ceiling D80 where the opening is formed or that a spacebetween outer surface D53 and the mentioned side surface is as small aspossible. A reflection layer or a reflector that reflects the lightreceived from second light source D60 and guides the light to lightemission surface D52 may be formed in outer surface D53.

FIG. 39 is a block diagram illustrating a control configuration ofillumination apparatus D1. Focusing on the control configuration ofillumination apparatus D1, illumination apparatus D1 includes controllerD70, storage D71, first light source D20, and second light source D60.Here, storage D71, first light source D20, and second light source D60are connected to controller D70.

Controller D70 controls operations of first light source D20 and secondlight source D60, such as turning the light on, turning the light off,dimming, and toning (adjusting the color of light emitted or the colortemperature). Controller D70 is realized by a microcomputer, aprocessor, or a specialized circuit, for example.

Controller D70 obtains information regarding an image stored in storageD71, and controls the light emission of first light source D20 accordingto the information. For example, when a blue sky is to be projected onlight diffuser D40, controller D70 obtains information regarding a bluesky from storage D71, and controls the light emission of the pluralityof light-emitting elements D22 based on the information obtained. Insuch a manner, by controlling the light emission of each light-emittingelement D22 using controller D70, illumination apparatus D1 projectslight having an image, such as an image of a blue sky, a white cloud, acloudy sky, an evening sky, or a sunset, on light diffuser D40.

Meanwhile, controller D70 causes light emission component D50 to radiatelight, in other words, causes second light source D60 to emit light suchthat the light projected on light diffuser D40 is inhibited fromappearing on inner wall surface Dw1 (li_(g)ht emission surface D52) ofillumination apparatus D1. When doing so, controller D70 controls secondlight source D60 such that light emission component D50 radiates lightin the same color as the color of ceiling D80 in which illuminationapparatus D1 is installed.

FIG. 40 illustrates an example of a light emission state of illuminationapparatus D1. For example, when the color of ceiling D80 is white,controller D70 controls the light emission of second light source D60such that light emission component D50 radiates white light.Alternatively, controller D70 controls the light emission of secondlight source D60 according to the color of the light projected on lightdiffuser D40 such that the color of inner wall surface Dw1 becomes thesame as the color of the surroundings such as ceiling D80 as a result.Such control reduces the feeling of strangeness generated due to innerwall surface Dw1 of illumination apparatus D1 being irradiated with thelight from light diffuser D40.

[Advantageous Effects Etc.]

Illumination apparatus D1 according to Embodiment 4 includes: case D10having opening portion D11; first light source D20 disposed in case D10and including a plurality of light-emitting elements D22; light diffuserD40 which is disposed in opening portion D11, diffuses and transmitslight emitted from first light source D20, and from which the lightdiffused and the light transmitted exit; light emission component D50disposed outside light exit region D43 of light diffuser D40 on lightexit surface D42 side of light diffuser D40; and second light source D60that emits light to light emission component D50 to cause light emissioncomponent D50 to radiate light.

As described above, disposing light emission component D50 outside lightexit region D43 of light diffuser D40 makes it possible to form, in asurface of light emission component D50, inner wall surface Dw1connecting the ceiling surface and light diffuser D40, for example.According to this configuration, even when inner wall surface Dw1, thatis, a surface of light emission component D50, is irradiated with thelight exiting from light diffuser D40, it is possible to reduce theinfluence of the light from light diffuser D40 and the user's feeling ofstrangeness by causing light emission component D50 to radiate light.

Light emission component D50 may be disposed around light exit regionD43.

With this, even when inner wall surface Dw1 is viewed from variousdirections, it is possible to reduce the influence of the light fromlight diffuser D40 and the user's feeling of strangeness by causinglight emission component D50, that forms inner wall surface Dw1, toradiate light.

Light emission component D50 may be a light guide plate having lightemission surface D52.

By using a light guide plate as light emission component D50 asdescribed above, light emission component D50 can be thinner andillumination apparatus D1 can be smaller in size.

Light emission component D50 may be disposed such that light emissionsurface D52 intersects light exit surface D42 of light diffuser D40 andfaces an inside of light exit region D43 opposite an outside of lightexit region D43.

With this, the light from light emission component D50 can exit throughthe inner surface (light emission surface D52) irradiated with the lightfrom light diffuser D40, and it is possible to efficiently reduce theinfluence of the light from light diffuser D40 and reduce the user'sfeeling of strangeness.

Second light source D60 may include light-emitting element D62 thatemits light of three primary colors.

With this, for example, second light source D60 can emit light in acolor that is the same as or similar to the color of a part of abuilding such as ceiling D80, and it is possible to form inner wallsurface Dw1 natural to the user. Further, for example, second lightsource D60 can emit light according to the color of light from lightdiffuser D40, and it is possible to efficiently reduce the influence ofthe light from light diffuser D40 and reduce the user's feeling ofstrangeness.

Illumination apparatus D1 may further include controller D70 thatcontrols light emission of first light source D20 and light emission ofsecond light source D60.

With this, it is possible to change the light projected on lightdiffuser D40 using first light source D20 and change the light radiatedfrom light emission component D50 using second light source D60. As aresult, for example, even when the image or color of the light projectedon light diffuser D40 changes, it is possible to reduce the influence ofthe light from light diffuser D40 and the user's feeling of strangenessby causing light emission component D50 to radiate light according tothe change.

[Examples 1 and 2 of Light Emission State of Illumination Apparatus]

Next, other examples (Examples 1 and 2) of the light emission state ofillumination apparatus D1 will be described with reference to FIG. 41and FIG. 42. The configuration of illumination apparatus D1 is the sameas that of illumination apparatus D1 according to Embodiment 4 describedabove, and thus the description will be omitted. Here, other examples ofthe light emission state of illumination apparatus D1 will be described.

FIG. 41 illustrates Example 1 of the light emission state ofillumination apparatus D1.

First, controller D70 obtains an image dependent on a time of day fromstorage D71, and displays the image on light diffuser D40. For example,when the time of day during which illumination apparatus D1 is used is8:00 am-4:00 pm, controller D70 obtains an image of the daytime storedin storage D71, e.g., an image including a blue sky, and causes theplurality of light-emitting elements D22 to emit light based on theimage. Note that the image may be a plain image.

Meanwhile, when the color of the light projected on light diffuser D40as described above is blue, controller D70 causes light emissioncomponent D50 to radiate light having a color temperature (for example,at least 5000 K and at most 7000 K) lower than the color temperature ofblue light (for example, at least 10000 K and at most 15000 K).

In FIG. 41, light diffuser D40 is illustrated in light shading and iscolored in blue. In contrast, inner wall surface Dw1 is in a colorsubstantially the same as the color of ceiling D80 as a result of lightemission component D50 radiating light having a color temperature lowerthan the color temperature of blue light. With controller D70controlling the color temperature of the light from light emissioncomponent D50 in this manner, the light from light diffuser D40 isinhibited from appearing on inner wall surface Dw1.

FIG. 42 illustrates Example 2 of the light emission state ofillumination apparatus D1.

First, controller D70 obtains an image dependent on a time of day fromstorage D71, and displays the image on light diffuser D40. For example,when the time of day at which illumination apparatus D1 is used is 6:00pm, controller D70 obtains an image including an evening sky stored instorage D71, and causes the plurality of light-emitting elements D22 toemit light based on the image.

Meanwhile, when the color of the light projected on light diffuser D40as described above is orange, controller D70 causes light emissioncomponent D50 to radiate light having a color temperature (for example,at least 5000 K and at most 7000 K) higher than the color temperature oforange light (for example, at least 2000 K and at most 3000 K).

In FIG. 42, light diffuser D40 is illustrated in dark shading and iscolored in orange. In contrast, inner wall surface Dw1 is in a colorsubstantially the same as the color of ceiling D80 as a result of lightemission component D50 radiating light having a color temperature higherthan the color temperature of orange light. With controller D70controlling the color temperature of the light from light emissioncomponent D50 in this manner, the light from light diffuser D40 isinhibited from appearing on inner wall surface Dw1.

With illumination apparatus D1 according to Examples 1 and 2 ofEmbodiment 4, controller D70 controls the light emission of second lightsource D60 such that the color temperature of the light radiated fromlight emission component D50 is different from the color temperature ofthe light exiting from light diffuser D40. With this, light emissioncomponent D50, that is inner wall surface Dw1, can be brought into astate closer to the state of being irradiated with natural light, and itis thus possible to reduce the user's feeling of strangeness.

[Example 3 of Light Emission State of Illumination Apparatus]

Next, Example 3 of the light emission state of illumination apparatus D1will be described with reference to FIG. 43.

FIG. 43 illustrates Example 3 of the light emission state ofillumination apparatus D1. Although the configuration of illuminationapparatus D1 in Example 3 is the same as that of illumination apparatusD1 in Embodiment 4 described above, at least two light emissioncomponents D50 among four light emission components D50 a, D50 b, D50 c,and D50 d radiate light in different brightness or in different colors.

First, controller D70 obtains an image dependent on a time of day fromstorage D71, and displays the image on light diffuser D40. For example,when the time of day at which illumination apparatus D1 is used is 8:00am, controller D70 obtains an image including a sunrise stored instorage D71, and causes the plurality of light-emitting elements D22 toemit light based on the image.

Meanwhile, when the sunrise projected on light diffuser D40 as describedabove is located at a position which is, in light exit surface D42 oflight diffuser D40, closer to light emission component D50 d, controllerD70 controls the light emission of light emission component D50 aopposed to light emission component D50 d such that the sunrise lesseasily appears on light emission component D50 a. Further, dimmingcontrol or toning control is performed on light emission components D50b, D50 c, and D50 d such that they do not radiate light or that thesunrise less easily appears on them.

Furthermore, when the time of day at which illumination apparatus D1 isused is 6:00 pm, controller D70 obtains an image of an evening stored instorage D71, and causes the plurality of light-emitting elements D22 toemit light based on the image.

Meanwhile, when a sunset projected on light diffuser D40 as describedabove is located at a position which is, in light exit surface D42 oflight diffuser D40, closer to light emission component D50 a (notillustrated), controller D70 controls the light emission of lightemission component D50 d opposed to light emission component D50 a suchthat the sunset less easily appears on light emission component D50 d.Further, dimming control or toning control is performed on lightemission components D50 a, D50 b, and D50 c such that they do notradiate light or that the sunset less easily appears on them.

In illumination apparatus D1 according to Example 3 of Embodiment 4, aplurality of light emission components D50 a to D50 d, each being lightemission component D50, are provided, and the plurality of lightemission components D50 a to D50 d include a first light emissioncomponent (e.g., D50 a) and a second light emission component (e.g., D50b). A plurality of second light sources D60, each being second lightsource D60, are also provided, and the plurality of second light sourcesD60 include a first-second light source corresponding to the firstemission component and a second-second light source corresponding to thesecond emission component. Controller D70 controls the light emission ofthe first-second and second-second light sources such that a lightemission state of the first light emission component is different from alight emission state of the second light emission component.

With this, light emission components D50 a to D50 d that make up innerwall surface Dw1 can be brought into a state closer to the state ofbeing irradiated with natural light, and it is thus possible to reducethe user's feeling of strangeness.

[Variation 8]

Next, illumination system D2 according to a variation of Embodiment 4(Variation 8) will be described. In illumination system D2, lightemission component D50 and second light source D60 illustrated inEmbodiment 4 are disposed not in illumination apparatus D1 but in a partof a building such as ceiling D80.

FIG. 44 is a cross sectional view of illumination system D2. FIG. 45 isa block diagram illustrating a control configuration of illuminationsystem D2.

As illustrated in FIG. 44 and FIG. 45, illumination system D2 includes:illumination apparatus D1A including case D10, first light source D20,and light diffuser D40; light-emitting equipment D85 including lightemission component D50 and second light source D60; and illuminationcontroller D75.

Note that illumination apparatus D1A of illumination system D2 isdifferent from the illumination apparatus according to Embodiment 4 inthat light entrance surface D41 of light diffuser D40 is in contact withedge surface D12 of case D10. Other than that, the configurations ofcase D10, first light source D20, and light diffuser D40 aresubstantially the same as those of illumination apparatus D1 describedin Embodiment 4, and thus, the descriptions will be omitted.

In the present variation, light emission component D50 and second lightsource D60 included in light-emitting equipment D85 are disposed inceiling D80 that is an example of a part of a building.

Second light source D60 is a light emission source that emits lighttoward light emission component D50 to cause light emission componentD50 to radiate light. Second light source D60 is disposed in recess D81of ceiling D80. Second light source D60 is an LED line module includingboard D63 and a plurality of light-emitting elements D62 mounted onboard D63.

Each light-emitting element D62 is an RGB-type element that emits lightof three primary colors. The plurality of light-emitting elements D62are arranged in a line at equal spaces on board D63. Second light sourceD60 is fixed to ceiling D80 such that the plurality of light-emittingelements D62 face upper surface D54 of light emission component D50.

Light emission component D50 is a light guide plate having lightemission surface D52. Light emission component D50 is disposed inceiling D80 such that light emission component D50 is disposed on lightexit surface D42 side of light diffuser D40 and located outside lightexit region D43. Illumination system D2 includes four light emissioncomponents D50. Four light emission components D50 are disposed aroundrectangular light exit region D43. Each light emission component D50 isdisposed such that light emission surface D52 intersects light exitsurface D42 of light diffuser D40 and faces the inside of light exitregion D43 opposite the outside of light exit region D43.

Light emission component D50 includes: outer surface D53 opposite lightemission surface D52; upper surface D54 located on recess D81 side ofceiling D80; and bottom surface D55 located on the floor surface sideopposite the side where upper surface D54 is disposed.

Light emission component D50 is attached to ceiling D80 in a state ofbeing in contact with notch D82 formed in ceiling D80. Light emissioncomponent D50 is fixed to ceiling D80 by fitting or screwing, forexample. Light emission component D50 receives, through upper surfaceD54, the light emitted from second light source D60, and radiates lightfrom light emission surface D52 via the light guide plate.

Light-emitting equipment D85 is installed in ceiling D80 such thatbottom surface D55 of light emission component D50 is flush with (liesin the same surface as) the ceiling surface. Bottom surface D55 isformed in the same color as the color of the ceiling surface byattaching a cloth or by painting. Light-emitting equipment D85 isinstalled such that outer surface D53 of light emission component D50 isin contact with the side surface of ceiling D80 or that a space betweenouter surface D53 and the side surface of ceiling D80 is small. Areflection layer or a reflector for reflecting the light received fromsecond light source D60 and guiding the light to light emission surfaceD52 is formed in outer surface D53. Light-emitting equipment D85 can bealso referred to as a luminaire or an illumination apparatus.

As illustrated in FIG. 45, focusing on the control configuration,illumination system D2 includes illumination controller D75,illumination apparatus D1A, and light-emitting equipment D85.Illumination apparatus D1A includes controller D70, storage D71, andfirst light source D20. Here, storage D71 and first light source D20 areconnected to controller D70. Light-emitting equipment D85 includessecond light source D60.

Illumination controller D75 controls operations of first light sourceD20 and second light source D60, such as turning the light on, turningthe light off, dimming, and toning. Illumination controller D75 isrealized by a microcomputer, a processor, or a specialized circuit, forexample.

Illumination controller D75 obtains information regarding an imagestored in storage D71 of illumination apparatus D1A, and controls thelight emission of first light source D20 via controller D70. Forexample, when a blue sky is to be projected on light diffuser D40,illumination controller D75 obtains information regarding a blue skyfrom storage D71, and controls the light emission of the plurality oflight-emitting elements D22 based on the information obtained. In such amanner, by controlling the light emission of each light-emitting elementD22 using illumination controller D75, illumination system D2 projectslight having an image such as an image of a blue sky, a white cloud, acloudy sky, an evening sky, or a sunset, on light diffuser D40.

Meanwhile, illumination controller D75 causes light emission componentD50 to radiate light, in other words, causes second light source D60 toemit light such that the light projected on light diffuser D40 isinhibited from appearing on inner wall surface Dw1 of illuminationapparatus D1A (light emission surface D52). Further, illuminationcontroller D75 controls second light source D60 such that light emissioncomponent D50 radiates light having the same color as the color ofceiling D80.

When the color of ceiling D80 is beige, for example, illuminationcontroller D75 controls the light emission of second light source D60such that light emission component D50 radiates beige light.Alternatively, illumination controller D75 controls the light emissionof second light source D60 according to the color of the light projectedon light diffuser D40 such that the color of inner wall surface Dw1becomes the same as the color of the surroundings such as ceiling D80 asa result. Such control reduces the feeling of strangeness generated dueto light irradiation of inner wall surface Dw1 of illumination systemD2.

Illumination system D2 according to the present variation includes:illumination apparatus D1A including case D10 having opening portionD11, first light source D20 disposed in case D10 and including aplurality of light-emitting elements D22, and light diffuser D40 whichis disposed in opening portion D11, diffuses and transmits light emittedfrom first light source D20, and from which the light diffused and thelight transmitted exit; light-emitting equipment D85 including lightemission component D50 disposed outside light exit region D43 of lightdiffuser D40 on light exit surface D42 side of light diffuser D40, andsecond light source D60 that emits light to light emission component D50to cause light emission component D50 to radiate light; and illuminationcontroller D75 that controls light emission of first light source D20and light emission of second light source D60.

As described above, disposing light emission component D50 outside lightexit region D43 of light diffuser D40 makes it possible to form, in asurface of light emission component D50, inner wall surface Dw1connecting the ceiling surface and light diffuser D40, for example.According to this configuration, even when inner wall surface Dw1, thatis, a surface of light emission component D50, is irradiated with thelight exiting from light diffuser D40, it is possible to reduce theinfluence of the light from light diffuser D40 and the user's feeling ofstrangeness by causing light emission component D50 to emit light.

Other Variations of Embodiment 4

Hereinbefore, the present disclosure has been described based onEmbodiment 4; however, the present disclosure is not limited toEmbodiment 4.

Although, in Embodiment 4, recess D56 is formed in upper surface D54 oflight emission component D50 and second light source D60 is housed inrecess D56, the position in which second light source D60 is housed isnot limited to upper surface D54 of light emission component D50. Forexample, as illustrated in (a) of FIG. 46, recess D14 may be formed inedge surface D12 of case D10, and second light source D60 may be housedin recess D14. Further, as illustrated in (b) of FIG. 46, recess D57 maybe formed in bottom surface D55 of light emission component D50, andsecond light source D60 may be housed in recess D57.

Although Embodiment 4 has presented the example where an image of a bluesky is projected on light diffuser D40, the image is not limited tothis. For example, the image may be an image of a blue sky with a whitecloud or an image of an evening sky with a sunset. Moreover, the imagemay be video showing a white cloud moving in a blue sky or video showingthe sun setting in an evening sky. Even in this case, by controlling thelight emission of light emission component D50 using controller D70, itis possible to reduce generation of the feeling of strangeness caused bythe appearance, on inner wall surface Dw1, of an image displayed onlight diffuser D40.

Although Embodiment 4 etc. have illustrated the example whereillumination apparatuses D1 and D1A are recessed in ceiling D80, thepresent disclosure is not limited to this. For example, illuminationapparatuses D1 and D1A may be recessed in a wall, that is a type of apart of a building.

Although Embodiment 4 etc. have illustrated the example where four lightemission components D50 surround light exit region D43, the shape oflight emission component D50 is not limited to a plate shape. The shapeof light emission component D50 may be a frame shape or a tubular shape.

Although Embodiment 4 etc. have illustrated the example where a lightguide plate of an edge light type is used as light emission componentD50, light emission component D50 is not limited to this. Light emissioncomponent D50 may be a luminaire of internal illumination. Further,second light source D60 need not be disposed in the vicinity of lightemission component D50, and may be disposed away from light emissioncomponent D50 and emit light to light emission component D50 via anoptical fiber etc.

Although Embodiment 4 has presented the example where one light diffuserD40 is used, the number of light diffusers is not limited to one, and aplurality of light diffusers may be used. Specifically, another lightdiffuser may be inserted between light diffuser D40 and light source D20to further diffuse the light.

For example, illumination apparatus D1 according to Embodiment 4includes case D10 having opening portion D11; first light source D20disposed in case D10 and including a plurality of light-emittingelements D22; light diffuser D40 which is disposed in opening portionD11, diffuses and transmits light emitted from first light source D20,and from which the light diffused and the light transmitted exit; andlight emission component D50 disposed outside light exit region D43 oflight diffuser D40 on light exit surface D42 side of light diffuser D40.

For example, as illustrated in FIG. 47, FIG. 48, and FIG. 49, part ofthe plurality of light-emitting elements D22 included in first lightsource D20 may emit light to light emission component D50.

For example, light exit region D43 may be rectangular, and lightemission component D50 may be disposed around four sides of light exitregion D43.

For example, light emission component D50 may be a light guide platehaving light emission surface D52, and light emission surface D52 may beorthogonal to light exit surface D42 of light diffuser D40.

Controller D70 may have the functions of at least one of controllersA50, B50, and C50.

Embodiment 5

Conventionally, an illumination apparatus is disclosed that includes: adisplay unit (a liquid crystal display) that displays an image; alight-emitting unit (a backlight) that emits outgoing light to anillumination region; and an image generation unit that generates animage (see, for example, Japanese Unexamined Patent ApplicationPublication No. 2013-92616). This illumination apparatus creates(reproduces) a lighting environment into which light streams, using thedisplay unit and the light-emitting unit.

It is desirable that an illumination apparatus reproduce a display image(e.g., the look of the sky) without causing discomfort. For example,when the display image reproduced by the illumination apparatus is flat,a user has difficulty experiencing a sensation that the user sees thesky through a window from the inside of a room. In other words, the userfeels uncomfortable with the display image reproduced by theillumination apparatus.

In view of this, Embodiment 5 has an object to provide an illuminationapparatus capable of reproducing a display image with less discomfort.

The following describes an illumination apparatus according toEmbodiment 5 with reference to FIG. 50 to FIG. 55. The illuminationapparatus according to Embodiment 5 is an apparatus that allows a userto virtually experience a sensation that the user sees the sky through awindow from the inside of a room. For example, the illuminationapparatus is installed in an indoor location and virtually produceslight (hereinafter referred to as virtual outdoor light) simulating thesky in nature (e.g., a blue sky or a sky at sunset). It should be notedthat a case in which the illumination apparatus is recessed in a ceiling(an exemplary part of a building) will be described in Embodiment 5. Inaddition, visible light may be simply referred to as light in theSpecification.

[Configuration of Illumination Apparatus]

First, the following describes a configuration of the illuminationapparatus according to Embodiment 5 with reference to FIG. 50 to FIG.52. FIG. 50 is a perspective view of external appearance of illuminationapparatus E1 according to Embodiment 5. FIG. 51 is a perspective view ofexternal appearance of illumination apparatus E1 according to Embodiment5 from which case E10 is removed. FIG. 52 is an exploded perspectiveview of illumination apparatus E1 according to Embodiment 5.

As illustrated in FIG. 50 to FIG. 52, illumination apparatus E1 includescase E10, light-emitting module E20, light reflector E30, light diffuserE40, controller E50, and power source EGO.

Case E10 is a case body that houses light-emitting module E20, lightreflector E30, light diffuser E40, controller E50, and power source EGO.

As illustrated in FIG. 50, case E10 is a low-profile box and has asubstantially rectangular shape in a plan view. It should be noted thatcase E10 is not limited to the substantially rectangular shape, and mayhave a shape such as a substantially circular shape, a substantiallymultangular shape, and a substantially semicircular shape, that is, isnot limited to any particular shape.

Case E10 includes housing portion E11 and frame portion E12.

Housing portion E11 is a low-profile box that houses light-emittingmodule E20, light reflector E30, light diffuser E40, controller E50, andpower source EGO. It should be noted that controller E50 and powersource E60 need not be housed in housing portion E11, and may bedisposed outside of case E10, for example. Housing portion E11 has anopening (hereinafter referred to as a first opening) in a surface(hereinafter referred to as a bottom surface) on the floor side (thenegative side of the Z axis), and houses light diffuser E40 to cover thefirst opening. In other words, the first opening corresponds in size tolight diffuser E40. In Embodiment 5, the first opening has asubstantially rectangular shape in a plan view.

Frame portion E12 is a ring-like (frame-like) member having asubstantially rectangular shape in a plan view, and is disposed in anedge portion of the bottom surface of housing portion E11. In otherwords, frame portion E12 is disposed on the bottom surface of housingportion E11 to surround the first opening of housing portion E11. Forthis reason, when illumination apparatus E1 is seen in a plan view, anopening (hereinafter referred to as a second opening) of frame portionE12 and the first opening have a substantially identical shape. InEmbodiment 5, the second opening has the substantially same rectangularshape as the first opening.

Light emitted from light diffuser E40 passes through the second opening.It should be noted that frame portion E12 is not limited to thesubstantially rectangular shape as long as frame portion E12 allowslight emitted from light diffuser E40 to pass, and frame portion E12 mayhave a shape such as a substantially circular shape, a substantiallymultangular shape, and a substantially semicircular shape, that is, isnot limited to any particular shape. For example, frame portion E12 hasan external body that may have the same shape as housing portion E11 ina plan view.

Frame portion E12 has bottom surface portion E12 a and upright portionE12 b. Illumination apparatus E1 is recessed in a ceiling so that bottomsurface portion E12 a is flush with a ceiling surface, for example. Inother words, bottom surface portion E12 a is a surface that the user cansee. For this reason, bottom surface portion E12 a may be designed inharmony with the ceiling surface. For example, bottom surface portionE12 a may be designed to imitate a ceiling pattern or a window frame. Itshould be noted that the ceiling surface is an exemplary installationsurface of a part of a building.

Upright portion E12 b is provided in a substantially vertical directionfrom an end portion of bottom surface portion E12 a on a side facing thesecond opening toward a side opposite to the floor surface (a directionof the positive side of the Z axis). If upright portion E12 b is notprovided and light diffuser E40 is disposed flush with the ceiling, itappears to the user that the ceiling is a thin board (e.g., a thin boardapproximately as thick as light diffuser E40), and the user may havedifficulty feeling as if a window that is a part of a building actuallyexists. Accordingly, in Embodiment 5, upright portion E12 b is providedfrom a standpoint of simulating a window that is more realistic. Forexample, upright portion E12 b has a height (a length in the Z-axisdirection) which allows the user to perceive board thickness of theceiling in which illumination apparatus E1 is recessed. Specifically,upright portion E12 b has a height of at least 30 mm or may have aheight approximately as much as a thickness from a roof to the ceiling.

Case E10 is made of, for example, a metal material or an non-metalmaterial having high thermal conductivity. Examples of the non-metalmaterial having high thermal conductivity include a resin having a highthermal conductance rate (a high thermal conductive resin). Using amaterial having high thermal conductivity as case E10 makes it possibleto radiate heat generated by light-emitting module E20 to the outsidevia case E10. It should be noted that housing portion E11 and frameportion E12 may be each made of a different material.

A portion of light emitted from light diffuser E40 enters uprightportion E12 b. In order to effectively use the light, upright portionE12 b may be made of a material having light-reflecting properties.Upright portion E12 b may be made of a metal material or a materialhaving a high light reflectance. For example, upright portion E12 b maybe formed of a hard resin material and covered with an evaporated metalfilm (a metal reflective film) made of a metal material such as silveror aluminum.

It should be noted that housing portion E11 and frame portion E12 may beintegrally formed to constitute case E10, or housing portion E11 andframe portion E12 may be separate bodies, and case E10 may be formed byjoining housing portion E11 and frame portion E12 with an adhesive.

As illustrated in FIG. 51, light-emitting module E20 is a light sourcethat emits virtual outdoor light for forming a display image.Light-emitting module E20 is fixed to an end portion (an end portion onthe positive side of the Z axis) of light reflector E30 opposite tolight diffuser E40. In addition, as illustrated in FIG. 52,light-emitting module E20 includes board E21 and light-emitting elementsE22 mounted on board E21.

Board E21 is a printed circuit board for mounting light-emittingelements E22 and is formed into a substantially rectangular shape. Forexample, a resin-based board, a metal-based board, or a ceramic boardmay be used as board E21.

A light-absorbing layer that is formed by black coating a layer toabsorb visible light is disposed on a surface of board E21 on the floorside. This is because, in the case of an illumination apparatus that,like illumination apparatus E1 according to Embodiment 5, reproduces adisplay image by being directly seen by a user, it is sometimesdesirable that the illumination apparatus look dark even if externallight enters the illumination apparatus when the illumination apparatusis turned off. In other words, in the case of the illumination apparatusthat is directly seen, it is sometimes desirable that a contrast ratiobe high between when the illumination apparatus is turned on and whenthe illumination apparatus is turned off. That the light-absorbing layeris disposed on the surface of board E21 on the floor side allows, evenif external light enters illumination apparatus E1 from the floor sidewhen illumination apparatus E1 is turned off, the surface of board E21on the floor side to absorb the external light. In other words, theexternal light entering illumination apparatus E1 is not reflected byboard E21. In consequence, illumination apparatus E1 looks dark whenillumination apparatus E1 is turned off. It should be noted that theexpression “look dark” is intended to include a case in whichillumination apparatus E1 is completely dark and a case in whichillumination apparatus E1 is dark to such a degree that it is possibleto recognize that illumination apparatus E1 is turned off. Moreover, theexternal light is light other than light emitted by illuminationapparatus E1, and is sunlight or illumination light, for example.Furthermore, for example, the black coating is performed beforelight-emitting elements E22 are mounted on board E21.

It should be noted that although the example in which thelight-absorbing layer is disposed on the surface of board E21 on thefloor side is described, the present disclosure is not limited to this.For example, a light-reflecting layer that reflects visible light may bedisposed on the surface of board E21 on the floor side. Furthermore, forexample, a specular reflection layer that specularly reflects incidentlight may be disposed on the surface of board E21 on the floor side. Itis possible to effectively use light reflected by light reflector E30 toform a display image because that the specular reflection layer isdisposed on the surface of board E21 on the floor side makes it possibleto further reflect, toward light diffuser E40, light emitted fromlight-emitting module E20 and reflected by light diffuser E40.

Light-emitting elements E22 are light-emitting diode (LED) elements. InEmbodiment 5, light-emitting elements E22 are RGB-type LED elements thatemit blue light, green light, and red light (i.e., the three primarycolors of light). It should be noted that light-emitting elements E22are not limited to the RGB-type LED elements. For example,light-emitting elements E22 may be RGBW-type LED elements that emit bluelight, green light, red light, and white light, or LED elements thatemit blue light and white light. In addition, light-emitting elementsE22 may be other LED elements. Light-emitting elements E22 are disposedon the surface of board E21 on the floor side. For example,light-emitting elements E22 are arranged in a matrix on the surface ofboard E21 on the floor side. For example, light-emitting elements E22are disposed at equal intervals.

It should be noted that the LED elements may be surface-mount device(SMD) LED elements or chip-on-board (COB) LED elements.

Moreover, although not shown, board E21 is provided with a control linethat is a line for transmitting a control signal from controller E50,and a power line that is a line for supplying power from power sourceEGO. For example, the control line and the power line are provided sothat light-emitting elements E22 are connected in series to the controlline and the power line. Each of light-emitting elements E22 receivespower from power source E60 via the power line, and emits predeterminedlight based on a control signal from the control line. In Embodiment 5,light-emitting elements E22 are capable of emitting light of variouscolors by adjusting luminance of blue light, green light, and red lightbecause light-emitting elements E22 are the RGB-type LED elements. Inconsequence, light-emitting elements E22 are capable of emitting virtualoutdoor light simulating, for example, a blue sky, a cloudy sky, or asky at sunset.

As illustrated in FIG. 52, light reflector E30 is an optical member thatis disposed to surround light-emitting elements E22 and has reflectingproperties for light emitted from light-emitting elements E22. In otherwords, light reflector E30 reflects light emitted from light-emittingelements E22 and entering light reflector E30. Specifically, lightreflector E30 reflects light entering an inner surface of lightreflector E30 (namely, a surface of light reflector E30 on a side facinglight-emitting elements E22) from light-emitting elements E22, towardlight diffuser E40. Light reflector E30 has a reflectance of, forexample, at least 80%.

In Embodiment 5, light reflector E30 includes wall E31 surroundinglight-emitting elements E22. In other words, light reflector E30 is aframe-like member surrounding light-emitting elements E22. It should benoted that light reflector E30 is not limited to a frame-like shape. Aslong as light reflector E30 includes wall E31 surrounding light-emittingelements E22, light reflector E30 is not limited to any particularshape. It should be noted that wall E31 is disposed to be, for example,substantially orthogonal to board E21. Specifically, an inner surface ofwall E31 (see inner surface E32 in FIG. 53) is disposed to besubstantially orthogonal to board E21. A normal of wall E31 (e.g., anormal relative to inner surface E32, and in FIG. 53, a straight lineparallel to the Y axis) may be inclined to a plane along the surface ofboard E21 in approximately 10 degrees. The normal of wall E31 furthermay be inclined to a plane along the surface of board E21 inapproximately 30 degrees. The normal of wall E31 may be inclined to aplane along the surface of board E21 in greater than 30 degrees.

The user can see a display image (hereinafter also referred to as a realimage) formed by light emitted from light-emitting elements E22 andentering light diffuser E40 without going through wall E31, and adisplay image (hereinafter also referred to as a reflected image) formedby light emitted from light-emitting elements E22, reflected by wallE31, and entering light diffuser E40. In other words, the real image andthe reflected image constitute one display image. When light reflectorE30 is not provided, a display image is formed of only the real imageand is approximately as large as board E21. In contrast, when the realimage and the reflected image constitute a display image, it is possibleto reproduce the display image larger than board E21. For example, it ispossible to reproduce a display image that appears to infinitely expand(e.g., a blue sky that appears to infinitely expand). Furthermore, boardE21 can be made smaller because providing light reflector E30 makes itpossible to reproduce a display image that is more extensive. In otherwords, illumination apparatus E1 can be downsized. In addition, it ispossible to reduce the number of light-emitting elements E22 to bemounted on light-emitting module E20.

Light reflector E30 is formed by performing, for example, a diffusiontreatment on a reflective plate made of a metal material such asaluminum (Al) and having a specular surface. Examples of the diffusiontreatment include a frosting treatment such as an anodizing treatment.It should be noted that the diffusion treatment may be performed on atleast the inner surface of light reflector E30 (wall E31).

The following describes a difference in how a display image looks vialight diffuser E40 between a case in which the diffusion treatment isperformed on wall E31 and a case in which the diffusion treatment is notperformed on wall E31, with reference to FIG. 53. FIG. 53 is a diagramfor illustrating a difference in how a display image looks depending onthe presence or absence of a diffusion treatment on light reflector E30according to Embodiment 5. Specifically, (a) in FIG. 53 is a diagramillustrating how light reflected by light reflector E30 on which thediffusion treatment is not performed looks, and (b) in FIG. 53 is adiagram illustrating how light reflected by light reflector E30 on whichthe diffusion treatment is performed looks.

As illustrated in (a) in FIG. 53, light is specularly reflected whichentered wall E31 on which the diffusion treatment is not performed, thatis, wall E31 having a specular surface. As described above, the usersees a real image and a reflected image as one display image. For thisreason, it is desirable that the real image and the reflected image arehard to distinguish. When the reflected image is a specular image,continuity of brightness between the reflected image and the real imageis maintained, but that the reflected image is the specular image ismore easily noticed. In other words, an effect of simulating a sky isreduced, and the user is likely to feel discomfort with the displayimage.

In contrast, as illustrated in (b) in FIG. 53, light is diffuselyreflected which entered light reflector E30 having inner surface E32 (asurface of wall E31 on a side facing light-emitting module E20) on whichanodized layer E33 is disposed by the anodizing treatment, that is,light reflector E30 not having the specular surface on inner surfaceE32. As a result, a reflected image formed becomes a slightly blurredimage, and thus the user is less likely to recognize that the reflectedimage is a specular image. In other words, the user is less likely tofeel discomfort with the display image. In this case, light reflectorE30 includes wall E31 and anodized layer E33. It should be noted thatthe anodizing treatment is an example of the diffusion treatment, andanodized layer E33 is an exemplary diffusion layer. It should also benoted that light-reflecting properties include diffusely reflectingproperties.

It should be noted that the diffusion treatment performed on lightreflector E30 does not include a white treatment. When light reflectorE30 is a whitish reflective plate, light reflected by the whitishreflective plate shines substantially evenly. As a result, for example,a sense of resolution between the sky and cloud of the reflected imageis lost, which reduces the effect of simulating the sky. Moreover, innersurface E32 of light reflector E30 may be the specular surface. Wheninner surface E32 of light reflector E30 is the specular surface, asdescribed above, the brightness between the real image and the reflectedimage has continuity, and it is possible to reproduce a display imagethat causes less discomfort compared to a case in which light reflectorE30 is white. Moreover, it is possible to reduce the loss of light fromlight-emitting module E20 because the light entering light reflector E30from light-emitting module E20 can be totally reflected toward lightdiffuser E40.

The following describes a height (a length in the Z-axis direction) oflight reflector E30 (wall E31). For example, when light reflector E30 isshort, light-emitting elements E22 appear granular, and the user islikely to feel discomfort with a display image. In contrast, although itis possible to reduce the granular appearance of light-emitting elementsE22 when light reflector E30 is tall, illumination apparatus E1 grows insize. Moreover, whether light-emitting elements E22 appear granulardepends on intervals (see distance Ed1 to be described later, in FIG.54) at which light-emitting elements E22 are mounted and a haze value oflight diffuser E40. In other words, in order to reduce the granularappearance of light-emitting elements E22, the height of light reflectorE30, the intervals at which light-emitting elements E22 are mounted, andthe haze value of light diffuser E40 are set.

It should be noted that when light reflector E30 is short (i.e., adistance between light-emitting module E20 and light diffuser E40 issmall), a display image to be reproduced is a flat image. For thisreason, light reflector E30 may be set high from a standpoint ofreproducing a display image giving a depth feel.

Light diffuser E40 is an optical member that diffuses light enteringfrom light-emitting module E20 and emits light toward the floor side.Specifically, light diffuser E40 is a diffusing panel that diffuseslight entering from light-entering surface E41 (a surface on thepositive side of the Z axis) of light diffuser E40 and emits light fromlight-outgoing surface E42.

Light diffuser E40 has translucency and diffusibility for light emittedfrom light-emitting module E20. Light diffuser E40 is produced byperforming, for example, diffusion processing on a resin material suchas transparent acryl or poly ethylene terephthalate (PET), or on atransparent plate made of glass. Light diffuser E40 has a hightransmittance by including a transparent material. For example, lightdiffuser E40 has a total transmittance of at least 80% or morepreferably at least 90%. With this, it is possible to reduce the loss oflight by light diffuser E40, and reproduce a bright display image.

Light diffuser E40 is produced by performing the diffusion treatment onthe transparent plate. The diffusion treatment is performed on at leastone of light-entering surface E41 and light-outgoing surface E42 oflight diffuser E40. Examples of the diffusion treatment include prismprocessing in which prisms including minute holes having a dot-likeshape (recesses) are formed. The minute holes are holes of a size whichdoes not allow the user to visually confirm the holes. The minute holeseach are, for example, a cone or a pyramid. For example, a depth (aheight of the cone) defined by the apex and bottom surface of the minutehole when the minute hole is the cone is at most 100 μm, and thediameter of the bottom surface of the minute hole is at most 100 pm. Asa result, illumination apparatus E1 allows the user to virtuallyexperience a sensation that the user sees the sky through a window fromthe inside of a room because the user cannot see the minute holes (theprisms). It should be noted that the prisms are not limited to theabove-described shapes or size, and a shape or size of the prisms isappropriately determined based on the haze value of light diffuser E40.For example, the prisms may be minute recesses having a dot-like shape.Furthermore, the diffusion treatment is not limited to the prismprocessing, and may be performed by surface texturing or printing.

The haze value of light diffuser E40 on which the diffusion treatment isperformed is, for example, at least 10% and at most 90%. Even when lightdiffuser E40 includes the transparent material, it is possible to reducethe granular appearance of light-emitting elements E22 of light-emittingmodule E20 for the user, by setting the haze value to be at least 10%.In addition, it is possible to maintain an outline of a reproduceddisplay image (e.g., an outline of cloud in a blue sky) to a certaindegree, by setting the haze value to be at most 90%. It should be notedthat the haze value can be adjusted based on, for example, the shape,size, etc. of the prisms formed in the prism processing.

It should be noted that light diffuser E40 is not limited to thetransparent plate (e.g., a transparent acrylic plate) on which thediffusion treatment is performed. For example, light diffuser E40 may beproduced by providing a diffusion sheet to a transparent plate. In thiscase, the diffusion sheet may be disposed on at least one of a surfaceof the transparent plate on the floor side and a surface of thetransparent plate on the side facing light-emitting module E20.

As described above, light diffuser E40 has a high total transmittanceand a high haze value. It should be noted that light diffuser E40 may bea milky-white diffuser panel in which a light diffusing material (e.g.,light-reflective minute particles such as silica particles) isdispersed. Such a diffuser panel is produced by resin molding atranslucent resin material mixed with a light diffusing material into apredetermined shape. It should be noted that although light diffuser E40may be milky white, light diffuser E40 may be made of, for example, atransparent resin material on which the diffusion treatment isperformed, from a standpoint of reducing the loss of light.

Light diffuser E40 is a rectangular plate in a plan view. Light diffuserE40 is fixed to an end portion (an end portion on the negative side ofthe Z axis) of light reflector E30 opposite to light diffuser E20. Inother words, light diffuser E40 is opposite to light-emitting module E20and is disposed to cover light-emitting module E20. Moreover, asillustrated in FIG. 50, light diffuser E40 is disposed to cover thefirst opening of case E10. For this reason, when the user looks up atthe ceiling, the user can visually confirm, of illumination apparatusE1, light diffuser E40, and bottom surface portion E12 a and uprightportion E12 b of frame portion E12.

Controller E50 is a control device that controls operations oflight-emitting module E20 such as lighting up, turning off, dimming, andtoning (adjustment of a color of emitted light or a color temperature),according to an instruction from the user (e.g., an instruction receivedvia a remote control or the like). For example, controller E50 obtainsinformation about a display image stored in a storage (not shown), andreproduces the display image based on the information. Specifically,when controller E50 receives, from the user, an instruction to display ablue sky as a display image, controller E50 obtains information aboutthe blue sky from the storage, and controls light-emitting module E20based on the information obtained. It should be noted that controllerE50 and light-emitting module E20 (light-emitting elements E22) areelectrically connected via a control line.

In Embodiment 5, light-emitting elements E22 are the RGB-type LEDelements. Accordingly, controller E50 outputs a control signal tolight-emitting elements E22 via the control line according to aninstruction from the user, the control signal including informationabout luminance of each of blue LEDs, green LEDs, and red LEDs.Light-emitting elements E22 that received the control signal emit bluelight, green light, and red light based on the control signal.

Controller E50 outputs a control signal to light-emitting module E20 attime intervals that, for example, do not cause a display image to moveunnaturally. Specifically, controller E50 outputs the control signalapproximately twenty times per second. With this, when, for example, adisplay image of moving cloud is reproduced, it is possible to reproducemore natural motion.

Controller E50 is implemented by, for example, a microcomputer, aprocessor, or a dedicated circuit.

In Embodiment 5, controller E50 is disposed on the surface oflight-emitting module E20 (board E21) opposite to another surface of thesame facing light diffuser E40.

Power source E60 includes: a power converter (e.g., a power convertercircuit) that converts AC power supplied from a power system (e.g., acommercial power source) into DC power; and a power circuit thatgenerates power for causing light-emitting module E20 (light-emittingelements E22) to emit light. For example, power source E60 converts ACpower supplied from a commercial power source into DC power having apredetermined level, by rectifying, smoothing, stepping down, etc. theAC power, and supplies the DC power to light-emitting module E20. Powersource E60 is electrically connected to the power system via, forexample, a power line.

In Embodiment 5, power source E60 is disposed on the surface oflight-emitting module E20 opposite to the other surface of the samefacing light diffuser E40. In other words, controller E50 and powersource E60 are coplanar.

Illumination apparatus E1 thus configured is capable of reproducing adisplay image giving a depth feel because a space surrounded by lightreflector E30 is provided between light-emitting module E20 and lightdiffuser E40. For example, illumination apparatus E1 is capable ofreproducing a display image giving a depth feel because, whenillumination apparatus E1 is seen from a different angle, how thedisplay image looks changes depending on an angle. In contrast, when adisplay image is reproduced using a display apparatus such as a liquidcrystal display, the same display image is seen even the displayapparatus is seen from a different angle. In other words, the user mayfeel discomfort with the display image because the display imagereproduced by the display apparatus is flat. Accordingly, compared to acase in which a display image is reproduced by the display apparatusetc, illumination apparatus E1 according to Embodiment 5 is capable ofreproducing a display image that causes less discomfort becauseillumination apparatus E1 is capable of rendering a depth feel.

[Positional Relationship Between Light-Emitting Elements and LightReflector]

Next, the following describes the disposition of light-emitting elementsE22 and light reflector E30 (wall E31) with reference to FIG. 54. FIG.54 is a cross-sectional view of illumination apparatus E1 according toEmbodiment 5, taken along line LIV-LIV in FIG. 51. It should be notedthat for convenience, light diffuser E40 is omitted in FIG. 54.

As illustrated in FIG. 54, light-emitting module E20 is disposed insideof wall E31 in Embodiment 5. In other words, light reflector E30 isdisposed to surround light-emitting module E20. It should be noted thatlight reflector E30 may surround light-emitting elements E22 included inlight-emitting module E20.

Distance Ed1 in the figure indicates a distance between each oflight-emitting elements E22 and each adjacent one of light-emittingelements E22 (e.g., a distance between the centers of adjacentlight-emitting elements E22 in a plan view), and is an example of afirst interval. For example, distance Ed1 is a distance between theoptical axes of adjacent light-emitting elements E22. Moreover, distanceEd2 in the figure indicates a distance between each light-emittingelement E22 disposed in the outmost of board E21 and wall E31 (i.e., adistance between the center of, among light-emitting elements E22, eachlight-emitting element E22 closest to wall E31 and inner surface E32 ofwall E31), and is an example of a second interval. For example, distanceEd2 is a distance between the optical axis of light-emitting element E22closest to wall E31 and inner surface E32 of wall E31. It should benoted that although FIG. 54 shows the example in which the distancebetween each one of light-emitting elements E22 and each adjacent one oflight-emitting elements E22 disposed in the Y-axis direction is distanceEd1, a distance between each one of light-emitting elements E22 and eachadjacent one of light-emitting elements E22 disposed in the X-axisdirection is also distance Ed1, for example.

A display image (a real image) formed by light entering light diffuserE40 from light-emitting elements E22 without going through wall E31 anda display image (a reflected image) formed by light entering lightdiffuser E40 after being emitted by light-emitting elements E22 andreflected by wall E31 may constitute a display image causing nodiscomfort. However, brightness of a boundary between the real image andthe reflected image changes according to distance Ed2 between, amonglight-emitting elements E22 mounted on board E21, each light-emittingelement E22 mounted on the outermost of board E21 and wall E31.Specifically, the boundary between the real image and the reflectedimage becomes darker with an increase in distance Ed2. In other words, adark line is formed at the boundary between the real image and thereflected image. Moreover, the boundary between the real image and thereflected image becomes brighter with a decrease in distance Ed2. Inother words, a bright line is formed at the boundary between the realimage and the reflected image. For the above reasons, the brightnessbetween the real image and the reflected image becomes discontinuous,which results in a display image causing discomfort.

When distance Ed2 is expressed as Ed1/2 using distance Ed1, the brightor dark line is less likely to be formed at the boundary between thereal image and the reflected image, and it is possible to reproduce adisplay image that causes less discomfort. It should be noted that inEmbodiment 5, the diffusion treatment is performed on inner surface E32of wall E31 and light diffuser E40, and a display image to be reproducedis a slightly blurred image. For this reason, distance Ed2 which doesnot cause the dark or bright line to be formed at the boundary betweenthe real image and the reflected image has a predetermined range. Forexample, when distance Ed2 is expressed as being greater than Ed1/4 andless than 3×Ed1/4 (Ed1/4<Ed2<3×Ed1/4) using distance Ed1, the sameeffect is produced as the case in which distance Ed2 is expressed asEd1/2. In other words, when distance Ed2 is expressed as being greaterthan Ed1/4 and less than 3×Ed1/4 using distance Ed1, the dark or brightline is less likely to be formed at the boundary between the real imageand the reflected image, and it is possible to reproduce a display imagethat causes less discomfort.

Moreover, out of the bright line and the dark line, the dark line isless noticeable. Accordingly, the maximum value of distance Ed2 may besmaller than that of distance Ed1, although this case produces a lesseffect than the case in which distance Ed2 is greater than Ed1/4 andless than 3×Ed1/4. In other words, distance Ed2 may be greater thanEd1/4 and less than Ed1 (Ed1/4<Ed2<Ed1). In consequence, it is possibleto reproduce a display image that causes less discomfort because thebright line is less likely to be formed at the boundary between the realimage and the reflected image and the dark line is less noticeable evenwhen the dark line is formed. It should be noted that in Embodiment 5,distance Ed2 is set Ed1/2.

Although FIG. 54 illustrates right and left distances Ed2 (distance Ed2on the positive side of the Y axis and distance Ed2 on the negative sideof the Y axis) are substantially equal distances, the present disclosureis not limited to this. Two distances Ed2 may each be a differentdistance as long as the different distance is within the range of fromEd1/4 to Ed1. In other words, distances Ed2 between light-emittingelements E22 disposed on the outermost of board E21 and wall E31 mayeach be a different distance as long as the different distance is withinthe range of from Ed1/4 to Ed1.

Illumination apparatus E1 thus configured is, for example, recessed inthe ceiling and used. Specifically, as illustrated in FIG. 55,illumination apparatus E1 is recessed in ceiling E70 and used. FIG. 55is a conceptual diagram illustrating an exemplary installation ofillumination apparatus E1 according to Embodiment 5. Illuminationapparatus E1 reproduces a display image that makes it difficult tovisually confirm a boundary between a real image and a reflected image,and by looking up illumination apparatus E1, the user thus can see thedisplay image that allows the user to virtually experience a sensationthat the user sees the sky through a window from the inside of a room(i.e., the display image that causes less discomfort). It should benoted that illumination apparatus E1 may be installed in, for example, afacility, an underground mall, or the like in which daylight is hard toobtain.

[Advantageous Effects Etc.]

Next, the following describes advantageous effects of illuminationapparatus E1 according to Embodiment 5.

Illumination apparatus E1 according to Embodiment 5 is to be disposed ina recess of ceiling E70 (an exemplary part of a building). Illuminationapparatus E1 includes: light-emitting module E20 that includes board E21and light-emitting elements E22 disposed on board E21; light diffuserE40 that has translucency and covers light-emitting module E20; andlight reflector E30 that includes wall E31 having light-reflectingproperties and surrounding light-emitting elements E22. Amonglight-emitting elements E22, every two adjacent light-emitting elementsE22 are disposed on board E21 at distance Ed1 (an example of a firstinterval). Distance Ed2 (an example of a second interval) is larger than¼ of distance Ed1 and smaller than distance Ed1, distance Ed2 being aninterval between wall E31 and light-emitting element E22 closest to wallE31 among light-emitting elements E22 (Ed1/4<Ed2<Ed1).

With this, distance Ed2 between, among light-emitting elements E22mounted on board E21, each light-emitting element E22 mounted on theoutermost of board E21 and wall E31 becomes greater than Ed1/4 andsmaller than Ed1. When distance Ed2 is greater than Ed1/4, it ispossible to keep a bright line from being formed at a boundary between areal image that is a display image formed by light emitted fromlight-emitting elements E22 and entering light diffuser E40 withoutgoing through wall E31 and a reflected image that is a display imageformed by light emitted from light-emitting elements E22, reflected bywall E31, and entering light diffuser E40. In addition, when distanceEd2 is smaller than distance Ed1, it is possible to make, even in thecase where a dark line is formed at the boundary between the real imageand the reflected image, the dark line less noticeable. In other words,illumination apparatus E1 according to Embodiment 5 is capable ofreproducing a display image which makes it difficult for the user torecognize the boundary between the real image and the reflected image.Stated differently, illumination apparatus E1 is capable of reproducingthe display image with less discomfort. Accordingly, illuminationapparatus E1 is capable of reproducing the display image more similar toa sensation that the user sees the sky through a window from the insideof a room.

Moreover, a surface of wall E31 on a side facing light-emitting moduleE20 is a specular surface.

With this, brightness between a reflected image (a specular image)formed by light reflected by the specular surface and a real image hascontinuity, and it is possible to reproduce a display image with lessdiscomfort compared to a case in which a diffusing member is white. Inaddition, when inner surface E32 of wall E31 is a specular surface, itis possible to reduce the loss of light from light-emitting module E20because the light entering wall E31 from light-emitting module E20 canbe totally reflected.

Moreover, a diffusion treatment is performed on a surface of wall E31 ona side facing light-emitting module E20. A surface of wall E31 on a sidefacing light-emitting module E20 is light-diffusive

With this, a reflected image formed by light reflected by wall E31becomes not a specular image but a slightly blurred image, and thus theuser is less likely to recognize that the reflected image is thespecular image. In other words, the user is less likely to feeldiscomfort with a display image formed of a real image and the reflectedimage that is not the specular image.

Moreover, the surface of wall E31 on the side facing light-emittingmodule E20 is not white.

With this, it is possible to reduce deterioration of the effect ofsimulating a sky, which is caused by the loss of the sense of resolutionbetween the sky and cloud of the reflected image resulting from lightreflected by wall E31 shining substantially evenly.

Moreover, light diffuser E40 has a total transmittance of at least 80%and a haze value of at least 10% and at most 90%.

With this, light diffuser E40 has, as optical properties, a hightransmittance and a high haze value. It is possible to efficiently uselight from light-emitting module E20 for a display image because theloss of light by light diffuser E40 is reduced due to the hightransmittance of light diffuser E40. In addition, it is possible toreduce granular appearance of light-emitting elements E22 and maintainan outline of a reproduced display image (e.g., an outline of cloud in ablue sky) to a certain degree because light diffuser E40 has the hazevalue of at least 10% and at most 90%.

Other Variations of Embodiment 5

Although the present disclosure is described based on Embodiment 5, thepresent disclosure is not limited to Embodiment 5.

For example, although the example in which the case includes the frameportion is described in Embodiment 5, the present disclosure is notlimited to this. For example, the frame portion may be configured as aportion of a part of a building. In other words, an illuminationapparatus does not include the frame portion and is fixed to the frameportion which is the portion of the part of the building. In the casewhere the case includes the frame portion, when the illuminationapparatus is attached to, for example, the ceiling, the user may see aboundary between the ceiling and the bottom surface of the frame portionand feel discomfort accordingly. In contrast, in the case where theframe portion is configured as the portion of the part of the building,the illumination apparatus does not include the frame portion, anddiscomfort to be felt by the user seeing the boundary between theceiling and the illumination apparatus can be reduced accordingly.

Moreover, although the example in which the illumination apparatus isrecessed in the ceiling is described in Embodiment 5, the presentdisclosure is not limited to this. For example, the illuminationapparatus may be recessed in a wall etc. In this case, the wall is anexemplary part of a building.

Moreover, although the example in which the diffusion treatmentperformed on the inner surface of the light reflector is the frosttreatment is described in Embodiment 5, the present disclosure is notlimited to this. For example, a treatment for roughening the innersurface of the light reflector such as blasting may be used as thediffusion treatment. Furthermore, in this case, a rugged portion made bysurface roughing is an example of the diffusion layer.

Moreover, although the example in which distance Ed1 (the example of thefirst interval) is the distance between the centers of thelight-emitting elements is described in Embodiment 5, the presentdisclosure is not limited to this. For example, distance Ed1 may be adistance between end portions of the light-emitting elements on thepositive side of the Y axis.

Moreover, although the example in which the illumination apparatusincludes the light reflector and the case is described in Embodiment 5,the present disclosure is not limited to this. For example, when thelight reflector has a closed-end cylindrical shape and houses each ofthe structural components, the illumination apparatus need not includethe case. In addition, when the internal surface of the case haslight-reflecting properties (i.e., when the case includes the wallsurrounding the light-emitting elements, and a surface of the wall onthe side facing the light-emitting elements has light-reflectingproperties), the illumination apparatus need not include the lightreflector. In this case, a distance between, among the light-emittingelements, each light-emitting element closest to the wall and thesurface of the wall on the side facing the light-emitting elements isthe second interval.

Moreover, although the example in which the light reflector is theframe-like member having the wall is described in Embodiment 5, thepresent disclosure is not limited to this. For example, the lightreflector may have a closed-end frame-like shape. In this case, thelight-emitting module is disposed so that the light-emitting elementsare on a side facing the opening of the light reflector with referenceto the board. In addition, the light reflector having the closed-endframe-like shape may include the wall surrounding the light-emittingelements and a bottom portion covering a surface opposite to a surfaceon which the light-emitting elements of the light-emitting module aremounted, and at least the wall may have reflecting properties for lightemitted by the light-emitting elements. The light reflector may includethe wall surrounding the light-emitting elements and havinglight-reflecting properties.

Moreover, although the example in which the light reflector is thereflective plate made of the metal material such as aluminum isdescribed in Embodiment 5, the present disclosure is not limited tothis. For example, the light reflector may be made of a hard resin, andan evaporated metal film (a metal reflective film) made of a metalmaterial such as aluminum may be provided to the inner surface of thelight reflector. In addition, the light reflector may be formed byjoining a metal tape such as an aluminum tape to a resin plate made of aresin material with an adhesive.

Moreover, although the example in which the controller causes thelight-emitting module to reproduce the display image according to theinstruction of the user is described in Embodiment 5, the presentdisclosure is not limited to this. For example, the controller mayobtain a look of the sky from an imaging device (e.g., a camera) thatcaptures the look of the sky, and may cause the light-emitting module toreproduce a display image similar to the look of the sky obtained.Accordingly, it is possible to reduce discomfort to be felt by the userwhen the user goes outside or inside because the display imagereproduced inside the room by the illumination apparatus and the actuallook of the sky outside are similar.

Moreover, although the example in which the controller reproduces thedisplay image according to the instruction of the user is described inEmbodiment 5, the present disclosure is not limited to this. Forexample, the controller may have a timer function, obtain, from thestorage, information about a display image corresponding to a time whenan instruction is received from the user, and control the light-emittingmodule based on the information obtained. Alternatively, the controllermay obtain, at a predetermined time, information about a display imagecorresponding to the predetermined time from the storage, and controlthe light-emitting module based on the information obtained.

Embodiment 6

Conventionally, an illumination apparatus is disclosed that includes: adisplay unit (a liquid crystal display) that displays an image; alight-emitting unit (a backlight) that emits outgoing light to anillumination region; and an image generation unit that generates animage (see, for example, Japanese Unexamined Patent ApplicationPublication No. 2013-92616). This illumination apparatus creates(reproduces) a lighting environment into which light streams, using thedisplay unit and the light-emitting unit.

It is desirable that an illumination apparatus reproduce a display image(e.g., the look of the sky) without causing discomfort. For example,when the display image reproduced by the illumination apparatus is flat,a user has difficulty experiencing a sensation that the user sees thesky through a window from the inside of a room. In other words, the userfeels uncomfortable with the display image reproduced by theillumination apparatus.

In view of this, Embodiment 6 has an object to provide an illuminationapparatus capable of reproducing a display image for which discomfort isreduced.

The following describes an illumination apparatus according toEmbodiment 6 with reference to FIG. 56 to FIG. 61. The illuminationapparatus according to Embodiment 6 is an apparatus that allows a userto virtually experience a sensation that the user sees the sky through awindow from the inside of a room. For example, the illuminationapparatus is installed in an indoor location and virtually produceslight (hereinafter referred to as virtual outdoor light) simulating thesky in nature (e.g., a blue sky or a sky at sunset) through an indoorwindow. It should be noted that a case in which the illuminationapparatus is recessed in a ceiling (an exemplary building element) willbe described in Embodiment 6. In addition, visible light may be simplyreferred to as light in the Specification.

[Configuration of Illumination Apparatus]

First, the following describes a configuration of the illuminationapparatus according to Embodiment 6 with reference to FIG. 56 to FIG.58. FIG. 56 is a perspective view of external appearance of illuminationapparatus F1 according to Embodiment 6. FIG. 57 is a perspective view ofexternal appearance of illumination apparatus F1 according to Embodiment6 from which case F10 is removed. FIG. 58 is an exploded perspectiveview of illumination apparatus F1 according to Embodiment 6.

As illustrated in FIG. 56 to FIG. 58, illumination apparatus F1 includescase F10, light-emitting module F20, light reflector F30, light diffuserF40, controller F50, and power source F60.

Case F10 is a case body that houses light-emitting module F20, lightreflector F30, light diffuser F40, controller F50, and power source F60.

As illustrated in FIG. 56, case F10 is a low-profile box and has asubstantially rectangular shape in a plan view. It should be noted thatcase F10 is not limited to the substantially rectangular shape, and mayhave a shape such as a substantially circular shape, a substantiallymultangular shape, and a substantially semicircular shape, that is, isnot limited to any particular shape.

Case F10 includes housing portion F11 and frame portion F12.

Housing portion F11 is a low-profile box that houses light-emittingmodule F20, light reflector F30, light diffuser F40, controller F50, andpower source F60. It should be noted that controller F50 and powersource F60 need not be housed in housing portion F11, and may bedisposed outside of case F10, for example. Housing portion F11 has anopening (hereinafter referred to as a first opening) in a surface(hereinafter referred to as a bottom surface) on the floor side (thenegative side of the Z axis), and houses light diffuser F40 to cover thefirst opening. In other words, the first opening corresponds in size tolight diffuser F40. In Embodiment 6, the first opening has asubstantially rectangular shape in a plan view.

Frame portion F12 is a ring-like (frame-like) member having asubstantially rectangular shape in a plan view, and is disposed in anedge portion of the bottom surface of housing portion F11. In otherwords, frame portion F12 is disposed on the bottom surface of housingportion F11 to externally surround the first opening of housing portionF11. For this reason, when illumination apparatus F1 is seen in a planview, an opening (hereinafter referred to as a second opening) of frameportion F12 and the first opening have a substantially identical shape.In Embodiment 6, the second opening has the substantially samerectangular shape as the first opening.

Light emitted from light diffuser F40 passes through the second opening.It should be noted that frame portion F12 is not limited to thesubstantially rectangular shape as long as frame portion F12 allowslight emitted from light diffuser F40 to pass, and frame portion F12 mayhave a shape such as a substantially circular shape, a substantiallymultangular shape, and a substantially semicircular shape, that is, isnot limited to any particular shape. For example, frame portion F12 hasan external body that may have the same shape as housing portion F11 ina plan view.

Frame portion F12 has bottom surface portion F12 a and upright portionF12 b. Illumination apparatus F1 is recessed in a ceiling surface sothat bottom surface portion F12 a is flush with the ceiling surface, forexample. In other words, bottom surface portion F12 a is a surface thatthe user can see. For this reason, bottom surface portion F12 a may bedesigned in harmony with the ceiling surface. For example, bottomsurface portion F12 a may be designed to imitate a ceiling pattern or awindow frame. It should be noted that the ceiling surface is anexemplary installation surface of a part of a building.

Upright portion F12 b is provided in a substantially vertical directionfrom an end portion of bottom surface portion F12 a on a side facing thesecond opening toward a side opposite to the floor surface (a directionof the positive side of the Z axis). If upright portion F12 b is notprovided and light diffuser F40 is disposed flush with the ceiling, itappears to the user that the ceiling is a thin board (e.g., a thin boardapproximately as thick as light diffuser F40), and the user may havedifficulty feeling as if a window that is a part of a building actuallyexists. Accordingly, in Embodiment 6, upright portion F12 b is providedfrom a standpoint of simulating a window that is more realistic. Forexample, upright portion F12 b has a height (a length in the Z-axisdirection) which allows the user to perceive board thickness of theceiling in which illumination apparatus F1 is recessed. Specifically,upright portion F12 b has a height of at least 30 mm or may have aheight approximately as much as a thickness from a roof to the ceiling.

Case F10 is made of, for example, a metal material or a non-metalmaterial having high thermal conductivity. Examples of the non-metalmaterial having high thermal conductivity include a resin having a highthermal conductance rate (a high thermal conductive resin). Using amaterial having high thermal conductivity as case F10 makes it possibleto radiate heat generated by light-emitting module F20 to the outsidevia case F10. It should be noted that housing portion F11 and frameportion F12 may be each made of a different material.

A portion of light emitted from light diffuser F40 enters uprightportion F12 b. In order to effectively use the light, upright portionF12 b may be made of a material having light-reflecting properties.Upright portion F12 b may be made of a metal material or a materialhaving a high light reflectance. For example, upright portion F12 b maybe formed of a hard resin material and covered with an evaporated metalfilm (a metal reflective film) made of a metal material such as silveror aluminum.

It should be noted that housing portion F11 and frame portion F12 may beintegrally formed to constitute case F10, or housing portion F11 andframe portion F12 may be separate bodies, and case F10 may be formed byjoining housing portion F11 and frame portion F12 with an adhesive.

As illustrated in FIG. 57, light-emitting module F20 is a light sourcethat emits virtual outdoor light for forming a display image.Light-emitting module F20 is fixed to an end portion of light reflectorF30 opposite to light diffuser F40 (an end portion on the positive sideof the Z axis). In addition, as illustrated in FIG. 58, light-emittingmodule F20 includes board F21 and light-emitting elements F22 mounted onboard F21.

Board F21 is a printed circuit board for mounting light-emittingelements F22 and is formed into a substantially rectangular shape. Forexample, a resin-based board, a metal-based board, or a ceramic boardmay be used as board F21.

In illumination apparatus F1 according to Embodiment 6, a specularreflection layer is disposed between board F21 and light diffuser F40having translucency and light diffusibility. The specular reflectionlayer is an optical member that specularly reflects light entering thespecular reflection layer from a side facing light diffuser F40. Thefollowing describes the specular reflection layer with reference to FIG.59. FIG. 59 is a cross-sectional view of illumination apparatus F1according to Embodiment 6, taken along line LIX-LIX in FIG. 57. Itshould be noted that a solid line and broken lines in FIG. 59 eachindicate light, and specifically, the solid line indicates light(outgoing light FW) emitted from light-emitting element F22, and thebroken lines each indicate light that is reflected. More specifically,reflected light FR1 indicated by one of the broken lines representslight reflected by light diffuser F40, which is included in outgoinglight FW, and reflected light FR2 indicated by the other of the brokenlines represents light reflected by specular reflection layer F23, whichis included in reflected light FR1. It should be noted that specularreflection layer F23 is an exemplary specular reflector.

Specular reflection layer F23 is formed by applying a specular finish toa surface of board F21 on the side facing light diffuser F40 (a surfaceon which light-emitting elements F22 are mounted in Embodiment 6) beforelight-emitting elements F22 are mounted on board F21. The specularfinish application includes applying or spraying a specular coatingmaterial (e.g., a coating material including pieces of aluminum). Itshould be noted that when board F21 is seen in a plan view, specularreflection layer F23 is formed in a region that does not overlaplight-emitting elements F22 and electrodes (not shown). Moreover,specular reflection layer F23 is disposed, via an insulating layer,above electric conductors such as lines (though not shown, linesincluding power lines and control lines) disposed on the surface ofboard F21 on the side facing light diffuser F40. In other words,specular reflection layer F23 is disposed to cover board F21 exceptlight-emitting elements F22 and the electrodes.

Furthermore, specular reflection layer F23 has a light reflectance of,for example, at least 80%.

When light enters such specular reflection layer F23 from light diffuserF40, the light is specularly reflected toward light diffuser F40 byspecular reflection layer F23. For example, as illustrated in FIG. 59, aportion of outgoing light FW emitted from light-emitting module F20 isreflected toward light-emitting module F20 by light diffuser F40.Reflected light FR1 reflected by light diffuser F40 is specularlyreflected toward light diffuser F40 by specular reflection layer F23because illumination apparatus F1 according to Embodiment 6 includesspecular reflection layer F23. In other words, specular reflection layerF23 is a reflecting member that reflects light emitted fromlight-emitting module F20. A display image is formed by light passingthrough light diffuser F40, which is included in outgoing light FW, andlight passing through light diffuser F40, which is included in reflectedlight FR2 specularly reflected by specular reflection layer F23. Inother words, it is possible to effectively use reflected light FR2reflected by light diffuser F40 as light for forming the display imagebecause illumination apparatus F1 includes specular reflection layerF23.

It should be noted that although FIG. 59 illustrates, as reflected lightFR2, only the light passing through light diffuser F40, a portion ofreflected light FR2 is reflected toward light-emitting module F20 bylight diffuser F40. Specular reflection layer F23 further specularlyreflects the reflected light. The above-described reflection repeatedlyoccurs between light-emitting module F20 and light diffuser F40.

It should be noted that conventionally, a light-diffusing layer thatdiffusely reflects light (e.g., a whitish layer in which lightreflective minute particles such as silica particles are dispersed) or alight-absorbing layer (e.g., a blackish layer that absorbs light) issometimes disposed on a surface of a board on which light-emittingelements are mounted (the surface on the floor side in Embodiment 6).Such a configuration, however, does not make it possible to effectivelyuse, for a display image, light emitted from a light-emitting module andreflected toward the light-emitting module by a light diffuser.

For example, when the light-diffusing layer is disposed in the board,reflected light reflected by a light reflector is diffusely reflected bythe light-diffusing layer. As a result, a display image formed by lightemitted from the light-emitting module and passing through the lightdiffuser and a display image formed by light diffusely reflected by thelight-diffusing layer and subsequently passing through the lightdiffuser differ in a degree of blur. Accordingly, the display images aredifferent from a sky that a user sees through a window from the insideof a room, which may cause the user to feel discomfort.

Embodiment 6 is characterized by disposing specular reflection layer F23and causing specular reflection layer F23 to specularly reflect enteringlight so that a display image more similar to an actual sky isreproduced. With this, a display image formed by light emitted fromlight-emitting module F20 and passing through light diffuser F40(hereinafter also referred to as a first display image) and a displayimage formed by light specularly reflected by specular reflection layerF23 and subsequently passing through light diffuser F40 (hereinafteralso referred to as a second display image) have a substantiallyidentical degree of blur. It should be noted that the second displayimage is an image formed by light specularly reflected by specularreflection layer F23 at least once and subsequently passing throughlight diffuser F40. As explained above, numerous reflections occurbetween specular reflection layer F23 and light diffuser F40.Consequently, the second display image is composed of images givingdifferent depth feels.

Light-emitting elements F22 are light-emitting diode (LED) elements. InEmbodiment 6, light-emitting elements F22 are RGB-type LED elements thatemit blue light, green light, and red light (i.e., the three primarycolors of light). It should be noted that light-emitting elements F22are not limited to the RGB-type LED elements. For example,light-emitting elements F22 may be RGBW-type LED elements that emit bluelight, green light, red light, and white light, or LED elements thatemit blue light and white light. In addition, light-emitting elementsF22 may be other LED elements. Light-emitting elements F22 are disposedon the surface of board F21 on the floor side. For example,light-emitting elements F22 are arranged in a matrix on the surface ofboard F21 on the floor side. For example, light-emitting elements F22are disposed at equal intervals.

It should be noted that the LED elements may be surface-mount device(SMD) LED elements or chip-on-board (COB) LED elements.

Moreover, although not shown, board F21 is provided with a control linethat is a line for transmitting a control signal from controller F50,and a power line that is a line for supplying power from power sourceF60. For example, the control line and the power line are provided sothat light-emitting elements F22 are connected in series to the controlline and the power line. Each of light-emitting elements F22 receivespower from power source F60 via the power line, and emits predeterminedlight based on a control signal from the control line. In Embodiment 6,light-emitting elements F22 are capable of emitting light of variouscolors by adjusting luminance of blue light, green light, and red lightbecause light-emitting elements F22 are the RGB-type LED elements. Inconsequence, light-emitting elements F22 are capable of emitting virtualoutdoor light simulating, for example, a blue sky, a cloudy sky, or asky at sunset.

As illustrated in FIG. 58, light reflector F30 is an optical member thatis disposed to surround light-emitting elements F22 and has reflectingproperties for light emitted from light-emitting elements F22. In otherwords, light-reflecting member F30 reflects light emitted fromlight-emitting elements F22 and entering light reflector F30.Specifically, light reflector F30 reflects light entering an innersurface of light reflector F30 (namely, a surface of light reflector F30on a side facing light-emitting elements F22) from light-emittingelements F22, toward light diffuser F40. Light reflector F30 has areflectance of, for example, at least 80%.

In Embodiment 6, light reflector F30 includes wall F31 surroundinglight-emitting elements F22. In other words, light reflector F30 is aframe-like member surrounding light-emitting elements F22. It should benoted that light reflector F30 is not limited to a frame-like shape. Aslong as light reflector F30 includes wall F31 surrounding light-emittingelements F22, light reflector F30 is not limited to any particularshape. It should be noted that light reflector F30 is an exemplary framethat includes a wall surrounding light-emitting elements F22, and thatthe frame need not have light-reflecting properties.

The user can see a display image (hereinafter also referred to as a realimage) formed by light emitted from light-emitting elements F22 andentering light diffuser F40 without going through wall F31, and adisplay image (hereinafter also referred to as a reflected image) formedby light emitted from light-emitting elements F22, reflected by wallF31, and entering light diffuser F40. In other words, the real image andthe reflected image constitute one display image. When light reflectorF30 is not provided, a display image is formed of only the real imageand is approximately as large as board F21. In contrast, when the realimage and the reflected image constitute a display image, it is possibleto reproduce the display image larger than board F21. For example, it ispossible to reproduce a display image that appears to infinitely expand(e.g., a blue sky that appears to infinitely expand). Furthermore, boardF21 can be made smaller because providing light reflector F30 makes itpossible to reproduce a display image that is more extensive. In otherwords, illumination apparatus F1 can be downsized. In addition, it ispossible to reduce the number of light-emitting elements F22 to bemounted on light-emitting module F20.

Light reflector F30 is formed by performing, for example, a diffusiontreatment on a reflective plate made of a metal material such asaluminum (Al) and having a specular surface. Examples of the diffusiontreatment include a frosting treatment such as an anodizing treatment.It should be noted that the diffusion treatment may be performed on atleast the inner surface of light reflector F30 (wall F31). Stateddifferently, light reflector F30 may have a diffusion layer inside wallF31. When wall F31 is a specular surface, a reflected image formed bylight reflected by wall F31 is a specular image. The user is likely torecognize that the reflected image is the specular image, which reducesthe effect of simulating the sky. On the other hand, as stated above,the frosting treatment causes a reflected image to be a slightly blurredimage. Consequently, the user is less likely to recognize that thereflected image is a specular image, which makes it harder for the userto feel discomfort with the display image. It should also be noted thatlight-reflecting properties include diffusely reflecting properties.

It should be noted that the diffusion treatment performed on lightreflector F30 does not include whitening. When light reflector F30 is awhitish reflective plate, light reflected by the whitish reflectiveplate shines substantially evenly. As a result, for example, a sense ofresolution between the sky and cloud of the reflected image is lost,which reduces the effect of simulating the sky. Moreover, the innersurface of light reflector F30 (the surface on the side facinglight-emitting elements F22) may be a specular surface. When the innersurface of light reflector F30 is the specular surface, as explainedabove, brightness between the real image and the reflected image hascontinuity, and it is possible to reproduce a display image that causesless discomfort compared to a case in which light reflector F30 iswhite. Moreover, it is possible to reduce the loss of light fromlight-emitting module F20 because the light entering light reflector F30from light-emitting module F20 can be totally reflected toward lightdiffuser F40.

The following describes a height (a length in the Z-axis direction) oflight reflector F30 (wall F31). For example, when light reflector F30 isshort, light-emitting elements F22 appear granular, and the user islikely to feel discomfort with a display image. In contrast, although itis possible to reduce the granular appearance of light-emitting elementsF22 when light reflector F30 is tall, illumination apparatus F1 grows insize. Moreover, whether light-emitting elements F22 appear granulardepends on intervals at which light-emitting elements F22 are mountedand a haze value of light diffuser F40. In other words, in order toreduce the granular appearance of light-emitting elements F22, theheight of light reflector F30, the intervals at which light-emittingelements F22 are mounted, and the haze value of light diffuser F40 areset.

It should be noted that when light reflector F30 is short (i.e., adistance between light-emitting module F20 and light diffuser F40 issmall), a display image to be reproduced is a flat image. For thisreason, light reflector F30 may be set high from a standpoint ofreproducing a display image giving a depth feel.

Light diffuser F40 is an optical member that diffuses light enteringfrom light-emitting module F20 and emits light toward the floor side.Specifically, light diffuser F40 is a diffusing panel that diffuseslight entering from light-entering surface F41 (a surface on thepositive side of the Z axis) of light diffuser F40 and emits light fromlight-outgoing surface F42.

Light diffuser F40 has translucency and diffusibility for light emittedfrom light-emitting module F20. Light diffuser F40 is produced byperforming, for example, diffusion processing on a transparent platemade of glass or a resin material such as transparent acryl or polyethylene terephthalate (PET). Light diffuser F40 has a hightransmittance by including a transparent material. For example, lightdiffuser F40 has a total transmittance of at least 80% or morepreferably at least 90%. With this, it is possible to reduce the loss oflight by light diffuser F40, and reproduce a bright display image.

Light diffuser F40 is produced by performing the diffusion treatment onthe transparent plate. The diffusion treatment is performed on at leastone of light-entering surface F41 and light-outgoing surface F42 oflight diffuser F40. Examples of the diffusion treatment include prismprocessing in which prisms including minute holes having a dot-likeshape (recesses) are formed. The minute holes are holes of a size whichdoes not allow the user to visually confirm the holes. The minute holeseach are, for example, a cone or a pyramid. For example, a depth (aheight of the cone) defined by the apex and bottom surface of the minutehole when the minute hole is the cone is at most 100 μm, and thediameter of the bottom surface of the minute hole is at most 100 pm. Asa result, illumination apparatus F1 allows the user to virtuallyexperience a sensation that the user sees the sky through a window fromthe inside of a room because the user cannot see the minute holes (theprisms). It should be noted that the prisms are not limited to theabove-described shapes or size, and a shape or size of the prisms areappropriately determined based on the haze value of light diffuser F40.Furthermore, the diffusion treatment is not limited to the prismprocessing, and may be performed by surface texturing or printing.

The haze value of light diffuser F40 on which the diffusion treatment isperformed is, for example, at least 10% and at most 90%. Even when lightdiffuser F40 includes the transparent material, it is possible to reducethe granular appearance of light-emitting elements F22 of light-emittingmodule F20 for the user, by setting the haze value to be at least 10%.In addition, it is possible to maintain an outline of a reproduceddisplay image (e.g., an outline of cloud in a blue sky) to a certaindegree, by setting the haze value to be at most 90%. It should be notedthat the haze value can be adjusted based on, for example, the shape,size, etc. of the prisms formed in the prism processing.

Moreover, a surface of light diffuser F40 on a side facinglight-emitting module F20 (light-entering surface F41) is a smoothsurface. The smooth surface is, for example, a surface having surfaceroughness Ra of at most 5. It is possible to increase a proportion ofreflected light FR1 to outgoing light FW illustrated in FIG. 59, bycausing the surface of light diffuser F40 on the side facinglight-emitting module F20 to be the smooth surface. For example, lightreflector F30 having the smooth surface has a light reflectance ofapproximately 5%. In other words, a proportion of light passing throughlight diffuser F40 to outgoing light FW is higher than a proportion oflight (reflected light FR1) reflected by light diffuser F40 to outgoinglight FW.

The smooth surface of light diffuser F40 on the side facinglight-emitting module F20 may be achieved by polishing the surface oflight diffuser F40 on the side facing light-emitting module F20 or byapplying surface coating for smoothing to the surface of light diffuserF40 on the side facing light-emitting module F20. Alternatively, thesmooth surface may be achieved by applying a transparent film to thesurface of light diffuser F40 on the side facing light-emitting moduleF20.

According to such a configuration, the first display image formed by thelight emitted from light-emitting module F20 and passing through lightdiffuser F40 and the second display image formed by the light specularlyreflected by specular reflection layer F23 and subsequently passingthrough light diffuser F40 differ in depth feel. The first display imageis an image that is brighter than the second display image and appearsahead of the second display image. The second display image is an imagethat is darker than the first display image and appears behind of thefirst display image. In other words, the user can see the second displayimage darker than the first display image, behind of the first displayimage. The user is likely to experience a depth feel (athree-dimensional feel) about a display image composed of the firstdisplay image and the second display image, by the second display imagebeing formed.

It should be noted that a light reflectance of light diffuser F40 is notlimited to 5%, and can be adjusted based on surface roughness etc. ofthe smooth surface. The light reflectance of light reflector F30 may belight reflectance that allows a display image causing less discomfort tobe reproduced, and may be 10% or 20%.

It should be noted that when the diffusion treatment is performed on thesurface of light diffuser F40 on the side facing light-emitting moduleF20, the smooth surface may be provided by applying a transparent filmetc. to the surface on which the diffusion treatment is performed.

Furthermore, antireflection processing is performed on a surface oflight diffuser F40 on the floor side (i.e., a surface from which lightfrom light-emitting module F20 is emitted) to reduce reflection ofexternal light reflected by upright portion F12 b of case F10 andentering light diffuser F40. The following describes the antireflectionprocessing with reference to FIG. 60. FIG. 60 is a diagram forexplaining reflection of light reflected by upright portion F12 b andentering light diffuser F40 depending on the presence or absence ofantireflection layer F44, and is an enlarged partial cross sectionalview of illumination apparatus F1 according to Embodiment 6, taken alongline LX-LX in FIG. 56. Specifically, (a) in FIG. 60 is a diagram forexplaining the reflection when the antireflection processing is notperformed on light diffuser F40, and (b) in FIG. 60 is a diagram forexplaining the reflection when the antireflection processing isperformed on light diffuser F40. It should be noted that forconvenience, in (a) in FIG. 60, the same components as (b) in FIG. 60are assigned the same reference signs.

First, as illustrated in (a) in FIG. 60, a case will be described inwhich the antireflection processing is not performed on light diffuserF40 (i.e., light diffuser F40 includes base F43). It should be notedthat base F43 is, for example, a transparent plate made of glass or aresin material such as transparent acryl or PET.

External light FL entering upright portion F12 b of case F10 from thefloor side is reflected by upright portion F12 b. For example, externallight FL is diffusely reflected by upright portion F12 b. In otherwords, at least a portion of external light FL is diffused toward lightdiffuser F40. In an illumination apparatus according to a comparativeexample, light entering light diffuser F40 (a portion of external lightFL) is diffused toward the floor side by light diffuser F40 because theantireflection processing is not performed on the surface of lightdiffuser F40 on the floor side. The user can see the reflection of thelight reflected by upright portion F12 b and entering light diffuser F40by seeing reflected light FR3 reflected by light diffuser F40.

The reflection of the light reflected by upright portion F12 b occursboth when illumination apparatus F1 is turned off and when illuminationapparatus F1 is turned on. The reflection of the light reflected byupright portion F12 b when illumination apparatus F1 is turned off mayspoil the aesthetic appearance of illumination apparatus F1. Inaddition, the reflection of the light reflected by upright portion F12 bwhen illumination apparatus F1 is turned on may cause an image generatedby the reflection and a display image being overlapped to be seen in anarea in which the reflection occurs, and the user may feel discomfortwith the display image accordingly. It should be noted that externallight FL is light that is different from light emitted by illuminationapparatus F1 and enters illumination apparatus F1. Examples of externallight FL include sunlight and illumination light.

In contrast, as illustrated in (b) in FIG. 60, a case will be describedin which antireflection layer F44 provided by the antireflectionprocessing is disposed on the surface light diffuser F40 on the floorside (i.e., light diffuser F40 includes base F43 and antireflectionlayer F44). Antireflection layer F44 is an optical member that istransparent and reduces reflection of external light FL reflected byupright portion F12 b on the surface of light diffuser F40 on the floorside. Examples of antireflection layer F44 include an antireflective(AR) coat layer provided by AR coating and an antireflection film layerprovided by applying a film having an antireflection function.

According to such a configuration, it is possible to reduce thereflection of the light (the portion of external light FL) enteringlight diffuser F40 from upright portion F12 b, toward the floor side. Asexplained above, the reflection of external light FL from uprightportion F12 b of case F10 to light diffuser F40 occurs both whenillumination apparatus F1 is turned on and when illumination apparatusF1 is turned off. For this reason, it is possible to enhance theappearance of illumination apparatus F1 both when illumination apparatusF1 is turned on and when illumination apparatus F1 is turned off, byantireflection layer F44 being disposed on the surface of light diffuserF40 on the floor side.

It should be noted that in Embodiment 6, antireflection layer F44 isdisposed and is, for example, the AR coat layer. Moreover, the presentdisclosure includes illumination apparatus F1 including light diffuserF40 which is illustrated in (a) in FIG. 60 and in which antireflectionlayer F44 is not disposed.

It should be noted that light diffuser F40 is not limited to thetransparent plate (e.g., a transparent acrylic plate) on which thediffusion treatment is performed. For example, light diffuser F40 may beproduced by providing a diffusion sheet to a transparent plate. In thiscase, the diffusion sheet may be applied to at least one of a surface ofthe transparent plate on the floor side and a surface of the transparentplate on the side facing light-emitting module F20.

As described above, light diffuser F40 has a high total transmittanceand a high haze value. It should be noted that light diffuser F40 may bea milky-white diffuser panel in which a light diffusing material (e.g.,light-reflective minute particles such as silica particles) isdispersed. Such a diffuser panel is produced by resin molding atranslucent resin material mixed with a light diffusing material into apredetermined shape. It should be noted that although light diffuser F40may be milky white, light diffuser F40 may be made of, for example, atransparent resin material on which the diffusion treatment isperformed, from a standpoint of reducing the loss of light.

Light diffuser F40 is a rectangular plate in a plan view. Light diffuserF40 is fixed to an end portion (an end portion on the negative side ofthe Z axis) of light reflector F30 opposite to light-emitting module 20.In other words, light diffuser F40 is opposite to light-emitting moduleF20 and is disposed to cover light-emitting module F20. Moreover, asillustrated in FIG. 56, light diffuser F40 is disposed to cover thefirst opening of case F10. For this reason, when the user looks up atthe ceiling, the user can visually confirm, of illumination apparatusF1, light diffuser F40, and bottom surface portion F12 a and uprightportion F12 b of frame portion F12.

Controller F50 is a control device that controls operations oflight-emitting module F20 such as lighting up, turning off, dimming, andtoning (adjustment of a color of emitted light or a color temperature),according to an instruction from the user (e.g., an instruction receivedvia a remote control or the like). For example, controller F50 obtainsinformation about a display image stored in a storage (not shown), andreproduces the display image based on the information. Specifically,when controller F50 receives, from the user, an instruction to display ablue sky as a display image, controller F50 obtains information aboutthe blue sky from the storage, and controls light-emitting module F20based on the information obtained. It should be noted that controllerF50 and light-emitting module F20 (light-emitting elements F22) areelectrically connected via a control line.

In Embodiment 6, light-emitting elements F22 are the RGB-type LEDelements. Accordingly, controller F50 outputs a control signal tolight-emitting elements F22 via the control line according to aninstruction from the user, the control signal including informationabout luminance of each of blue LEDs, green LEDs, and red LEDs.Light-emitting elements F22 having received the control signal emit bluelight, green light, and red light based on the control signal.

Controller F50 outputs a control signal to light-emitting module F20 attime intervals that, for example, do not cause a display image to moveunnaturally. Specifically, controller F50 outputs the control signalapproximately twenty times per second. With this, when, for example, adisplay image of moving cloud is reproduced, it is possible to reproducemore natural motion.

Controller F50 is implemented by, for example, a microcomputer, aprocessor, or a dedicated circuit.

In Embodiment 6, controller F50 is disposed on the surface oflight-emitting module F20 (board F21) opposite to another surface of thesame facing light diffuser F40.

Power source F60 includes: a power converter (e.g., a power convertercircuit) that converts AC power supplied from a power system (e.g., acommercial power source) into DC power; and a power circuit thatgenerates power for causing light-emitting module F20 (light-emittingelements F22) to emit light. For example, power source F60 converts ACpower supplied from a commercial power source into DC power having apredetermined level, by rectifying, smoothing, stepping down, etc. theAC power, and supplies the DC power to light-emitting module F20. Powersource F60 is electrically connected to the power system via, forexample, a power line.

In Embodiment 6, power source F60 is disposed on the surface oflight-emitting module F20 opposite to the other surface of the samefacing light diffuser F40. In other words, controller F50 and powersource F60 are coplanar.

Illumination apparatus F1 thus configured is, for example, recessed inthe ceiling and used. Specifically, as illustrated in FIG. 61,illumination apparatus F1 is recessed in ceiling F70 of a room and used.FIG. 61 is a conceptual diagram illustrating exemplary installation ofillumination apparatus F1 according to Embodiment 6. Illuminationapparatus F1 reproduces a display image giving a depth feel with thefirst display image and the second display image, and by looking up atillumination apparatus F1, the user can see the display image thatallows the user to virtually experience a sensation that the user seesthe sky through a window from the inside of a room (i.e., the displayimage that causes less discomfort). It should be noted that illuminationapparatus F1 may be installed in, for example, a facility, anunderground mall, or the like in which daylight is hard to obtain.

[Advantageous Effects Etc.]

Next, the following describes advantageous effects of illuminationapparatus F1 according to Embodiment 6.

Illumination apparatus F1 according to Embodiment 6 is to be disposed ina recess of ceiling F70 (an exemplary part of a building). Illuminationapparatus F1 includes: light-emitting module F20 that includes board F21and light-emitting elements F22 disposed on board F21; light diffuserF40 that has translucency and covers light-emitting module F20; specularreflection layer F23 (an example of the specular reflector) that isdisposed between light-emitting module F20 and light diffuser F40; andlight reflector F30 that includes wall F31 surrounding light-emittingelements F22. Light-emitting module F20 emits light toward lightdiffuser F40, and specular reflection layer F23 reflects light fromlight diffuser F40.

With this, light (e.g., reflected light FR1) emitted from light-emittingelements F22 and reflected by a surface of light diffuser F40 on a sidefacing light-emitting module F20 is reflected toward light diffuser F40by specular reflection layer F23 (an example of the light reflector). Inother words, the user can see a first display image formed by lightemitted from light-emitting module F20 and passing light diffuser F40,and a second display image formed by light emitted from light-emittingmodule F20, reflected by light diffuser F40 and specular reflectionlayer F23, and passing light diffuser F40. Stated differently, the usercan see one display image formed of the first display image and thesecond display image. The light forming the second display imagepropagates between light-emitting module F20 and light diffuser F40 fora longer distance than the light forming the first display image becausethe light forming the second display image is reflected by lightdiffuser F40 and specular reflection layer F23. For this reason, thesecond display image is formed behind of the first display image whenseen by the user. In other words, by the second display image beingformed, it is possible to reproduce a display giving a stronger depthfeel without upsizing the illumination apparatus. Thus, according toillumination apparatus F1 according to Embodiment 6, it is possible toreproduce the display image with less discomfort.

Moreover, the specular reflector is specular reflection layer F23disposed on a surface of board F21 on a side facing light diffuser F40.

With this, light reflected by light diffuser F40 can be furtherreflected toward light diffuser F40 by specular reflection layer F23. Inother words, by disposing specular reflection layer F23 on the surfaceof board F21 on the side facing light diffuser F40, it is possible toreproduce a display giving a depth feel without upsizing theillumination apparatus.

Moreover, a surface of light diffuser F40 on a side facinglight-emitting module F20 is a smooth surface.

With this, it is possible to increase a proportion of light emitted fromlight-emitting module F20 and reflected by the surface of light diffuserF40 on the side facing light-emitting module F20. In other words, it ispossible to cause the second display image formed by the light passinglight diffuser F40, which is included in reflected light FR2, to be amore bright image. Accordingly, it is possible to reproduce a displayimage with much less discomfort because the difference in brightnessbetween the first display image and the second display image can bereduced, compared to a case in which the surface of light diffuser F40on the side facing light-emitting module F20 is not the smooth surface.

Moreover, light diffuser F40 includes antireflection layer F44 on asurface opposite to a surface facing light-emitting module F20.

With this, when external light reflected by upright portion F12 b entersthe surface of light diffuser F40 on the side facing light-emittingmodule F20 (a surface on the floor side), it is possible to reducereflection of the entering light toward the floor side by light diffuserF40. In other words, it is possible to reduce reflection of lightreflected by upright portion F12 b and entering light diffuser F40. Thereflection of external light reflected by upright portion F12 b andentering light diffuser occurs both when illumination apparatus F1 isturned on and when illumination apparatus F1 is turned off. For thisreason, by disposing antireflection layer F44 on the surface of lightdiffuser F40 on the floor side, it is possible to reduce discomfortcaused by the display image when illumination apparatus F1 is turned onas well as to enhance the aesthetic appearance of illumination apparatusF1 when illumination apparatus F1 is turned off. It should be noted thatillumination apparatus F1 may include upright portion F12 b or a part ofa building may include upright portion F12 b.

(Variation 9)

The following describes an illumination apparatus according to Variation9 of Embodiment 6 with reference to FIG. 62 to FIG. 64. FIG. 62 is across-sectional view of illumination apparatus F1 a according toVariation 9, taken along line LIX-LIX in FIG. 57. FIG. 64 is afragmentary plan view of illumination apparatus F1 a according toVariation 9, in a state in which light diffuser F40 is omitted from FIG.57. It should be noted that differences from Embodiment 6 will be mainlydescribed in Variation 9, and descriptions of the same structuralcomponents are omitted or simplified. Illumination apparatus F1 aaccording to Variation 9 differs from the illumination apparatus ofEmbodiment 6 mainly in that a specular reflector includes a metal platehaving holes.

As illustrated in FIG. 62 and FIG. 64, illumination apparatus F1 aaccording to Variation 9 includes perforated metal plate F123 thatspecularly reflects, toward light diffuser F40 of board F21, reflectedlight FR1 reflected by light diffuser F40. Perforated metal plate F123is an exemplary specular reflector. In addition, perforated metal plateF123 is an exemplary metal plate having holes.

Perforated metal plate F123 has reflecting properties for light emittedfrom light-emitting module F20. Perforated metal plate F123 may be madeof a material having a high reflectance for the light emitted fromlight-emitting module F20. For example, perforated metal plate F123 isproduced by punching holes F123 a in a metal plate such as a copperplate, a stainless plate, or an aluminum plate. It should be noted thata specular reflector is not limited to be made of the metal plate. Forexample, a glass plate or a resin plate to which a specular surface isprovided by depositing aluminum etc. thereon may be used as the specularreflector. In this case also, holes are punched at locationscorresponding to respective light-emitting elements F22.

As illustrated in FIG. 62, perforated metal plate F123 is disposedbetween board F21 and light diffuser F40 and closer to board F21. InVariation 9, perforated metal plate F123 is disposed in proximity toboard F21. Holes F123 a of perforated metal plate F123 are holes throughwhich light emitted from light-emitting elements F22 is allowed to passtoward light diffuser F40. In other words, perforated metal plate F123is disposed to avoid blocking the light emitted from light-emittingelements F22. For this reason, holes F123 a of perforated metal plateF123 are made corresponding to respective light-emitting elements F22.For example, as illustrated in FIG. 64, holes F123 a are madecorresponding one-to-one with light-emitting elements F22. It should benoted that holes F123 a each have, for example, a substantially circularshape in a plan view. It should be noted that the substantially circularshape may be a circular shape or an elliptical shape.

Moreover, holes F123 a are made to cover light-emitting elements F22 ina plan view. Furthermore, holes F123 a are larger in area thanlight-emitting elements F22 in a plan view. This is because it isintended to reduce a decrease of light for reproducing a display imagecaused by light emitted from light-emitting elements F22 entering asurface of perforated metal plate F123 on the side facing light-emittingmodule F20. The size of holes F123 a is appropriately determined basedon, for example, light distribution characteristics of light-emittingelements F22 and a distance between perforated metal plate F123 andlight-emitting module F20. It should be noted that perforated metalplate F123 is fixed to, for example, light reflector F30.

Moreover, perforated metal plate F123 is disposed on the surface ofboard F21 on the side facing light diffuser F40 so that the centers ofholes F123 a are approximately aligned with the centers oflight-emitting elements F22. This makes it possible to further reducethe decrease of the light for reproducing the display image.

With this configuration, light emitted from light-emitting module F20and reflected by light diffuser F40 is specularly reflected toward lightdiffuser F40 by the surface of perforated metal plate F123 on the sidefacing light diffuser F40. It should be noted that perforated metalplate F123 may be disposed in proximity to light-emitting module F20from a standpoint of reproducing a display image giving a depth feel.

The following describes a positional relationship between light-emittingmodule F20 and perforated metal plate F123 and the size of holes F123 awith reference to FIG. 63. In what follows, a case will be described inwhich perforated metal plate F123 is disposed between light diffuser F40and surfaces of light-emitting elements F22 on the side facing lightdiffuser F40 (hereinafter also referred to as light-emitting surfaces).It should be noted that when perforated metal plate F123 is disposedbetween board F21 and the light-emitting surfaces of light-emittingelements F22, the following need not be applied. For example, whenperforated metal plate F123 is disposed between board F21 and thelight-emitting surfaces of light-emitting elements F22, the size ofholes F123 a of perforated metal plate F123 may be substantiallyidentical to the size of light-emitting elements F22.

FIG. 63 is an enlarged cross-sectional view of illumination apparatus F1a according to Variation 9, in dashed region LXIII in FIG. 62.

As illustrated in FIG. 63, where the radius of each of holes F123 a ofperforated metal plate F123 is denoted by Fr, an interval betweenlight-emitting elements F22 arranged in a matrix (a distance betweenadjacent ones of light-emitting elements F22) is denoted by Fd, a halfbeam angle of light (outgoing light FW) emitted from light-emittingelements F22 is denoted by θ, and a distance between board F21 andperforated metal plate F123 is denoted by Fh, the positionalrelationship (distance) between light-emitting module F20 and perforatedmetal plate F123 and the size of holes F123 a are determined so that thefollowing relationship is satisfied.Fd/2>Fr>Fh×tan θ  (Expression 1)

It is clear from Expression 1 that radius Fr of each hole F123 a issmaller than the half of interval Fd of light-emitting elements F22 andlarger than Fh×tan θ defined by distance Fh between board F21 andperforated metal plate F123 and half beam angle θ of outgoing light FWfrom light-emitting elements F22. Even when perforated metal plate F123is disposed between light diffuser F40 and the light-emitting surfacesof light-emitting elements F22, punching holes F123 a in perforatedmetal plate F123 to satisfy Expression 1 allows perforated metal plateF123 to avoid blocking outgoing light FW from light-emitting elementsF22.

It should be noted that interval Fd between adjacent light-emittingelements F22 indicates a distance between the centers of respectiveadjacent light-emitting elements F22 in a plan view or cross-sectionalview, and is, for example, a distance between optical axes of respectiveadjacent light-emitting elements F22. Moreover, the half beam angle isdefined as an angle formed by optical axis Fa and a direction in whichan intensity of light emitted from the light-emitting surfaces oflight-emitting elements F22 becomes half of the maximum intensity of thelight.

It should be noted that above Expression 1 is not limited to the case inwhich the specular reflector is perforated metal plate F123. Forexample, Expression 1 is applicable to a case in which specularreflection layer F23 according to Embodiment 6 is disposed between lightdiffuser F40 and the surfaces of light-emitting elements F22 on the sidefacing light diffuser F40.

It should be noted that although perforated metal plate F123 produced bypunching the holes in the metal plate is described above as theexemplary metal plate having the holes, a method of punching holes in ametal plate is not limited to this. For example, holes may be punched ina metal plate by cutting.

It should be noted that although the example in which perforated metalplate F123 is disposed between board F21 and light diffuser F40 andcloser to board F21 is described above, the present disclosure is notlimited to this. For example, perforated metal plate F123 may bedisposed in contact with the surface of board F21 on the side facinglight diffuser F40 via an insulating layer. Moreover, in this case,perforated metal plate F123 may be thinner than light-emitting elementsF22.

As above, the specular reflector included in illumination apparatus F1 aaccording to Variation 9 is perforated metal plate F123 having holesF123 a at the locations corresponding to light-emitting elements F22(the exemplary metal plate having the holes).

With this, it is possible to provide the same effect as in the case inwhich the specular reflector is specular reflection layer F23.

Moreover, the metal plate is disposed between light-emitting elementsF22 and light reflector F40.

With this, since it is possible to control a depth feel by adjusting themetal plate between light-emitting elements F22 and light reflector F40,it is possible to reproduce a display image with less discomfort.

Moreover, where an interval of adjacent two light-emitting elements F22among light-emitting elements F22 is denoted by Fd, a half beam angle ofoutgoing light from light-emitting elements F22 is denoted by θ, and adistance between board F21 and perforated metal plate F123 is denoted byFh, the radius Fr of each of holes F123 a is defined by the followingrelational expression.Fd/2>Fr>Fh×tan θ  (Expression 1)

With this, even when perforated metal plate F123 is disposed betweenlight diffuser F40 and the light-emitting surfaces of light-emittingelements F22, perforated metal plate F123 having holes F123 a satisfyingExpression 1 makes it possible to avoid blocking outgoing light FW fromlight-emitting elements F22.

Other Variations of Embodiment 6 Etc.

Although the present disclosure is described based on Embodiment 6 etc.,the present disclosure is not limited to Embodiment 6 etc.

For example, although the example in which the case includes the frameportion is described in Embodiment 6 etc., the present disclosure is notlimited to this. For example, the frame portion may be configured as aportion of a part of a building. In other words, an illuminationapparatus does not include the frame portion and is fixed to the frameportion which is the part of the building. In the case where the caseincludes the frame portion, when the illumination apparatus is attachedto, for example, a ceiling, the user may see a boundary between theceiling and the bottom surface of the frame portion and feel discomfortaccordingly. In contrast, in the case where the frame portion isconfigured as the part of the building, the illumination apparatus doesnot include the frame portion, and discomfort to be felt by the userseeing the boundary between the ceiling and the illumination apparatuscan be reduced accordingly.

Moreover, although the example in which the specular reflector isdisposed between the board and the light diffuser is described inEmbodiment 6 etc., the present disclosure is not limited to this. Forexample, when the board is transparent, the specular reflector may bedisposed on a side (the positive side of the Z axis) opposite to thelight diffuser with reference to the board. In other words, the board(the light-emitting module) may be disposed between the specularreflector and the light reflector. In this case, the specular reflectorneed not have the holes.

Moreover, although the example in which the holes of the perforatedmetal plate are larger in area than the light-emitting elements in aplan view is described in Embodiment 6 etc., the present disclosure isnot limited to this. For example, a lens that controls lightdistribution characteristics of light emitted from the light-emittingmodule may be disposed between the light-emitting module and theperforated metal plate, and the size of each of the holes may bedetermined based on light distribution characteristics of light passingthrough the lens.

Moreover, although the example in which the holes of the perforatedmetal plate have the substantially circular shape in a plan view isdescribed in Embodiment 6 etc., the present disclosure is not limited tothis. For example, the shape of the holes may be appropriatelydetermined based on light distribution characteristics of thelight-emitting elements.

Moreover, although the example in which the illumination apparatus isrecessed in the ceiling is described in Embodiment 6 etc., the presentdisclosure is not limited to this. For example, the illuminationapparatus may be recessed in a wall etc. In this case, the wall is anexemplary part of the building.

Moreover, although the example in which the diffusion treatmentperformed on the inner surface of the light reflector is the frosttreatment is described in Embodiment 6 etc., the present disclosure isnot limited to this. For example, a treatment for roughening the innersurface of the light reflector such as blasting may be used as thediffusion treatment.

Moreover, although the example in which the illumination apparatusincludes the light reflector and the case is described in Embodiment 6etc., the present disclosure is not limited to this. For example, whenthe light reflector has a closed-end cylindrical shape and houses eachof the structural components, the illumination apparatus need notinclude the case. In addition, when the internal surface of the case haslight-reflecting properties (i.e., when the case includes the frameportion surrounding the light-emitting elements, and a surface of theframe portion on the side facing the light-emitting elements haslight-reflecting properties), the illumination apparatus need notinclude the light reflector.

Moreover, although the example in which the light reflector is theframe-like member having the wall is described in Embodiment 6 etc., thepresent disclosure is not limited to this. For example, the lightreflector may have a closed-end frame-like shape. In this case, thelight-emitting module is disposed so that the light-emitting elementsare on a side facing the opening of the light reflector with referenceto the board. In addition, the light reflector having the closed-endframe-like shape may include the wall surrounding the light-emittingelements and a bottom portion covering a surface opposite to a surfaceon which the light-emitting elements of the light-emitting module aremounted, and at least the wall may have reflecting properties for lightemitted by the light-emitting elements. The light reflector may includethe wall surrounding the light-emitting elements and havinglight-reflecting properties.

Moreover, although the example in which the light reflector is thereflective plate made of the metal material such as aluminum isdescribed in Embodiment 6 etc., the present disclosure is not limited tothis. For example, the light reflector may be made of a hard resin, andan evaporated metal film (a metal reflective film) made of a metalmaterial such as aluminum may be provided to the inner surface of thelight reflector. In addition, the light reflector may be formed byjoining a metal tape such as an aluminum tape to a resin plate made of aresin material with an adhesive. Moreover, although the example in whichthe controller causes the light-emitting module to reproduce the displayimage according to the instruction of the user is described inEmbodiment 6 etc., the present disclosure is not limited to this. Forexample, the controller may obtain a look of the sky from an imagingdevice (e.g., a camera) that captures the look of the sky, and may causethe light-emitting module to reproduce a display image similar to thelook of the sky obtained. Accordingly, it is possible to reducediscomfort to be felt by the user when the user goes outside or insidebecause the display image reproduced inside the room by the illuminationapparatus and the actual look of the sky outside are similar.

Moreover, although the example in which the controller reproduces thedisplay image according to the instruction of the user is described inEmbodiment 6 etc., the present disclosure is not limited to this. Forexample, the controller may have a timer function, obtain, from thestorage, information about a display image corresponding to a time whenan instruction is received from the user, and control the light-emittingmodule based on the information obtained. Alternatively, the controllermay obtain, at a predetermined time, information about a display imagecorresponding to the predetermined time from the storage, and controlthe light-emitting module based on the information obtained.

While the foregoing has described one or more embodiments and/or otherexamples, it is understood that various modifications may be madetherein and that the subject matter disclosed herein may be implementedin various forms and examples, and that they may be applied in numerousapplications, only some of which have been described herein. It isintended by the following claims to claim any and all modifications andvariations that fall within the true scope of the present teachings.

What is claimed is:
 1. An illumination apparatus, comprising: a casehaving an opening portion; a light source disposed in the case, thelight source including a plurality of light-emitting elements; a lightdiffuser which is disposed in the opening portion, and diffuses andtransmits light emitted from the plurality of light-emitting elements;and a controller that controls light emission from the light source,wherein the controller: controls light emission from the plurality oflight-emitting elements to project an image simulating a sky on thelight diffuser, the image changing with time; and when changing thelight emission from the plurality of light-emitting elements changingthe image, controls the light emission from the light source to keep achange in at least one of (i) a light amount, (ii) a color temperature,and (iii) a spectral distribution of light emitted from the illuminationapparatus within a predetermined range.
 2. The illumination apparatusaccording to claim 1, wherein as the control of the light emission fromthe light source, when changing the light emission from the plurality oflight-emitting elements, the controller controls the light emission fromthe light source to keep a change in at least one of (i) a light amount,(ii) a color temperature, and (iii) a spectral distribution of lightexiting from the light diffuser of the illumination apparatus within thepredetermined range.
 3. The illumination apparatus according to claim 2,wherein the controller changes at least a part of the image to keep achange in at least one of (i) the light amount, (ii) the colortemperature, and (iii) the spectral distribution of the light within thepredetermined range.
 4. The illumination apparatus according to claim 3,wherein when the image is an image simulating a cloud and a blue sky,the controller changes the image to keep at least one of a change in aratio of a cloud region to the image as a whole and a change in a ratioof a blue sky region to the image as a whole within a predeterminedrange, the cloud region being a region of the cloud, the blue sky regionbeing a region of the blue sky.
 5. The illumination apparatus accordingto claim 3, wherein when the image is projected using white light andblue light, the controller changes the image to keep a change in a lightflux ratio within a predetermined range.
 6. The illumination apparatusaccording to claim 1, wherein the controller keeps a change in at leastone of (i) the light amount, (ii) the color temperature, and (iii) thespectral distribution of the light within the predeteimined range duringa unit time.
 7. The illumination apparatus according to claim 1, whereinthe controller controls the light emission from the light source to keepa change in at least one of (i) the light amount, (ii) the colortemperature, and (iii) the spectral distribution of the light emittedfrom the illumination apparatus within the predetermined range during apredetermined time of day.
 8. The illumination apparatus according toclaim 7, wherein the controller controls the light emission from thelight source to keep a change in at least one of (i) the light amount,(ii) the color temperature, and (iii) the spectral distribution of thelight emitted from the illumination apparatus within a predeterminedrange during a time of dawn, morning, daytime, or evening.
 9. Anillumination system, comprising: the illumination apparatus according toclaim 1; light-emitting equipment including a light-emitting sourcedifferent from the plurality of light-emitting elements of theillumination apparatus; and an illumination controller that controlslight emission from the illumination apparatus and light emission fromthe light-emitting equipment, wherein the illumination controller:controls the light emission from the plurality of light-emittingelements to project an image on the light diffuser of the illuminationapparatus, the image changing with time; and when changing the lightemission from the plurality of light-emitting elements, controls thelight emission from the light-emitting equipment to keep a change in atleast one of (i) a light amount, (ii) a color temperature, and (iii) aspectral distribution of light emitted from the illumination systemwithin a predetermined range.
 10. The illumination apparatus accordingto claim 1, wherein the controller is disposed on a surface of the lightsource opposite to the light diffuser.
 11. An illumination apparatus,comprising: a case having an opening portion; a light source disposed inthe case, the light source including a plurality of light-emittingelements and a plurality of light-emitting sources different from theplurality of light-emitting elements; a light diffuser which is disposedin the opening portion, and diffuses and transmits light emitted fromthe plurality of light-emitting elements; and a controller that controlslight emission from the plurality of light-emitting elements and lightemission from the plurality of light-emitting sources, wherein thecontroller: controls the light emission from the plurality oflight-emitting elements to project an image simulating a sky on thelight diffuser, the image changing with time; and when changing thelight emission from the plurality of light-emitting elements, controlsthe light emission from the plurality of light-emitting sources to keepa change in at least one of (i) a light amount, (ii) a colortemperature, and (iii) a spectral distribution of light emitted from theillumination apparatus within a predetermined range.
 12. Theillumination apparatus according to claim 11, wherein the controllerperforms at least one of the following control: control of a lightintensity of the plurality of light-emitting sources according to alight amount of light exiting from the light diffuser; and control of atone of the plurality of light-emitting sources according to a color ofthe light exiting from the light diffuser.
 13. The illuminationapparatus according to claim 11, wherein the controller controls atleast one of a light intensity and a tone of the plurality oflight-emitting sources according to a change of the image.
 14. Theillumination apparatus according to claim 11, wherein the controller isdisposed on a surface of the light source opposite to the lightdiffuser.
 15. An illumination apparatus, comprising: a case having anopening portion; a light source disposed in the case, the light sourceincluding a plurality of light-emitting elements; a light diffuser whichis disposed in the opening portion, and diffuses and transmits lightemitted from the plurality of light-emitting elements; and a controllerthat controls light emission from the light source, wherein thecontroller: controls light emission from the plurality of light-emittingelements to project an image simulating a sky on the light diffuser, theimage changing with time; and when changing the light emission from theplurality of light-emitting elements changing the image, controls thelight emission from the light source to keep a change in an amount oflight exiting from the light diffuser of the illumination apparatuswithin a predetermined range during a unit time.
 16. The illuminationapparatus according to claim 15, wherein the controller: controls thelight emission from the plurality of light-emitting elements to projectan image on the light diffuser, the image changing with time; and whenchanging the light emission from the plurality of light-emittingelements, controls the light emission from the light source to keep achange in a color temperature of the light exiting from the lightdiffuser of the illumination apparatus within a predetermined rangeduring the unit time.
 17. The illumination apparatus according to claim15, wherein the controller: controls the light emission from theplurality of light-emitting elements to project an image on the lightdiffuser, the image changing with time; and when changing the lightemission from the plurality of light-emitting elements, controls thelight emission from the light source to keep a change in a spectraldistribution of the light exiting from the light diffuser of theillumination apparatus within a predetermined range during the unittime.
 18. The illumination apparatus according to claim 15, wherein theunit time is at least 0.001 seconds and at most 1 second.
 19. Theillumination apparatus according to claim 15, wherein the controller isdisposed on a surface of the light source opposite to the lightdiffuser.
 20. An illumination apparatus, comprising: a case having anopening portion; a first light source including a plurality oflight-emitting elements disposed in the case; a second light sourcedifferent from the first light source and disposed outside the case; alight diffuser which is disposed in the opening portion, and diffusesand transmits light emitted from the plurality of light-emittingelements; and a controller that controls light emission from the firstlight source and light emission from the second light source, whereinthe controller: controls light emission from the plurality oflight-emitting elements to project an image simulating a sky on thelight diffuser, the image changing with time; and when changing theimage, controls the light emission from at least one of the first lightsource and the second light source to keep a change in at least one of(i) a light amount, (ii) a color temperature, and (iii) a spectraldistribution of light emitted from the illumination apparatus within apredetermined range.